feat: add security hardening, AppArmor, and ARM64 Raspberry Pi support (Phase 6)

Security hardening: bind kubeconfig server to localhost, mount hardening
(noexec/nosuid/nodev on tmpfs), sysctl network hardening, kernel module
loading lock after boot, SHA256 checksum verification for downloads,
kernel AppArmor + Audit support, complain-mode AppArmor profiles for
containerd and kubelet, and security integration test.

ARM64 Raspberry Pi support: piCore64 base extraction, RPi kernel build
from raspberrypi/linux fork, RPi firmware fetch, SD card image with 4-
partition GPT and tryboot A/B mechanism, BootEnv Go interface abstracting
GRUB vs RPi boot environments, architecture-aware build scripts, QEMU
aarch64 dev VM and boot test.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -1,9 +1,10 @@
 .PHONY: all fetch kernel build-cloudinit build-update-agent build-cross rootfs initramfs \
-       iso disk-image oci-image \
+       iso disk-image oci-image rpi-image \
-       test-boot test-k8s test-persistence test-deploy test-storage test-all \
+       kernel-arm64 rootfs-arm64 \
-       test-cloudinit test-update-agent \
+       test-boot test-k8s test-persistence test-deploy test-storage test-security test-all \
+       test-boot-arm64 test-cloudinit test-update-agent \
        bench-boot bench-resources \
-       dev-vm dev-vm-shell quick docker-build shellcheck \
+       dev-vm dev-vm-shell dev-vm-arm64 quick docker-build shellcheck \
        kernel-audit clean distclean help
 
 SHELL := /bin/bash
@@ -71,6 +72,24 @@ build-cross:
 	@echo "==> Cross-compiling for amd64 + arm64..."
 	$(BUILD_DIR)/scripts/build-cross.sh
 
+# =============================================================================
+# ARM64 Raspberry Pi targets
+# =============================================================================
+kernel-arm64:
+	@echo "==> Building ARM64 kernel for Raspberry Pi..."
+	$(BUILD_DIR)/scripts/build-kernel-arm64.sh
+
+rootfs-arm64:
+	@echo "==> Preparing ARM64 rootfs..."
+	TARGET_ARCH=arm64 $(BUILD_DIR)/scripts/fetch-components.sh
+	TARGET_ARCH=arm64 $(BUILD_DIR)/scripts/extract-core.sh
+	TARGET_ARCH=arm64 $(BUILD_DIR)/scripts/inject-kubesolo.sh
+
+rpi-image: rootfs-arm64 kernel-arm64
+	@echo "==> Creating Raspberry Pi SD card image..."
+	$(BUILD_DIR)/scripts/create-rpi-image.sh
+	@echo "==> Built: $(OUTPUT_DIR)/$(OS_NAME)-$(VERSION).rpi.img"
+
 # =============================================================================
 # Kernel validation
 # =============================================================================
@@ -101,6 +120,14 @@ test-storage: iso
 	@echo "==> Testing local storage provisioning..."
 	test/integration/test-local-storage.sh $(OUTPUT_DIR)/$(OS_NAME)-$(VERSION).iso
 
+test-security: iso
+	@echo "==> Testing security hardening..."
+	test/integration/test-security-hardening.sh $(OUTPUT_DIR)/$(OS_NAME)-$(VERSION).iso
+
+test-boot-arm64:
+	@echo "==> Testing ARM64 boot in QEMU..."
+	test/qemu/test-boot-arm64.sh
+
 test-all: test-boot test-k8s test-persistence
 
 # Cloud-init Go tests
@@ -163,6 +190,10 @@ dev-vm-debug: iso
 	@echo "==> Launching dev VM (debug mode)..."
 	hack/dev-vm.sh $(OUTPUT_DIR)/$(OS_NAME)-$(VERSION).iso --debug
 
+dev-vm-arm64:
+	@echo "==> Launching ARM64 dev VM..."
+	hack/dev-vm-arm64.sh
+
 # Fast rebuild: only repack initramfs + ISO (skip fetch/extract)
 quick:
 	@echo "==> Quick rebuild (repack + ISO only)..."
@@ -199,7 +230,7 @@ distclean: clean
 help:
 	@echo "KubeSolo OS Build System (v$(VERSION))"
 	@echo ""
-	@echo "Build targets:"
+	@echo "Build targets (x86_64):"
 	@echo "  make fetch              Download Tiny Core ISO, KubeSolo, dependencies"
 	@echo "  make kernel             Build custom kernel with CONFIG_CGROUP_BPF=y"
 	@echo "  make build-cloudinit    Build cloud-init Go binary"
@@ -213,25 +244,33 @@ help:
 	@echo "  make quick              Fast rebuild (re-inject + repack + ISO only)"
 	@echo "  make docker-build       Reproducible build inside Docker"
 	@echo ""
+	@echo "Build targets (ARM64 Raspberry Pi):"
+	@echo "  make kernel-arm64       Build ARM64 kernel from raspberrypi/linux"
+	@echo "  make rootfs-arm64       Extract + prepare ARM64 rootfs from piCore64"
+	@echo "  make rpi-image          Create Raspberry Pi SD card image with A/B partitions"
+	@echo ""
 	@echo "Test targets:"
 	@echo "  make test-boot          Boot ISO in QEMU, verify boot success"
 	@echo "  make test-k8s           Boot + verify K8s node reaches Ready"
 	@echo "  make test-persist       Reboot disk image, verify state persists"
 	@echo "  make test-deploy        Deploy nginx pod, verify Running"
 	@echo "  make test-storage       Test PVC with local-path provisioner"
+	@echo "  make test-security      Verify security hardening (AppArmor, sysctl, mounts)"
 	@echo "  make test-cloudinit     Run cloud-init Go unit tests"
 	@echo "  make test-update-agent  Run update agent Go unit tests"
 	@echo "  make test-update        A/B update cycle integration test"
 	@echo "  make test-rollback      Forced rollback integration test"
+	@echo "  make test-boot-arm64    ARM64 boot test in QEMU aarch64"
 	@echo "  make test-all           Run core tests (boot + k8s + persistence)"
 	@echo "  make test-integ         Run full integration suite"
 	@echo "  make bench-boot         Benchmark boot performance (3 runs)"
 	@echo "  make bench-resources    Benchmark resource usage (requires running VM)"
 	@echo ""
 	@echo "Dev targets:"
-	@echo "  make dev-vm         Launch interactive QEMU VM"
+	@echo "  make dev-vm         Launch interactive QEMU VM (x86_64)"
 	@echo "  make dev-vm-shell   Launch QEMU VM -> emergency shell"
 	@echo "  make dev-vm-debug   Launch QEMU VM with debug logging"
+	@echo "  make dev-vm-arm64   Launch ARM64 QEMU VM"
 	@echo "  make kernel-audit   Check kernel config against requirements"
 	@echo "  make shellcheck     Lint all shell scripts"
 	@echo ""

build/Dockerfile.builder

@@ -31,6 +31,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     syslinux \
     syslinux-common \
     syslinux-utils \
+    apparmor \
+    apparmor-utils \
+    gcc-aarch64-linux-gnu \
+    binutils-aarch64-linux-gnu \
+    git \
     wget \
     xorriso \
     xz-utils \

build/config/kernel-audit.sh

@@ -128,7 +128,12 @@ echo "Security:"
 check_config CONFIG_SECCOMP              recommended "Seccomp (container security)"
 check_config CONFIG_SECCOMP_FILTER       recommended "Seccomp BPF filter"
 check_config CONFIG_BPF_SYSCALL          recommended "BPF syscall"
-check_config CONFIG_AUDIT                recommended "Audit framework"
+check_config CONFIG_AUDIT                mandatory "Audit framework"
+check_config CONFIG_AUDITSYSCALL         mandatory "Audit system call events"
+check_config CONFIG_SECURITY             mandatory "Security framework"
+check_config CONFIG_SECURITYFS           mandatory "Security filesystem"
+check_config CONFIG_SECURITY_APPARMOR    mandatory "AppArmor LSM"
+check_config CONFIG_SECURITY_NETWORK     recommended "Network security hooks"
 echo ""
 
 # --- Crypto ---

build/config/modules-arm64.list

@@ -0,0 +1,81 @@
+# Kernel modules loaded at boot by init (ARM64 / Raspberry Pi)
+# One module per line. Lines starting with # are ignored.
+# Modules are loaded in order listed — dependencies must come first.
+
+# Network device drivers (loaded early so interfaces are available)
+# Note: no e1000/e1000e on ARM64 — those are x86 Intel NIC drivers
+virtio_net
+
+# Virtio support (for QEMU VMs — block, entropy)
+virtio_blk
+virtio_rng
+
+# Raspberry Pi specific (USB Ethernet on Pi 4 is built-in, no module needed)
+# Pi 5 uses PCIe ethernet, also typically built-in
+
+# Filesystem — overlay (required for containerd)
+overlay
+
+# Netfilter dependencies (must load before conntrack)
+nf_defrag_ipv4
+nf_defrag_ipv6
+
+# Netfilter / connection tracking (required for kube-proxy)
+nf_conntrack
+nf_nat
+nf_conntrack_netlink
+
+# nftables (modern iptables backend)
+nf_tables
+nft_compat
+nft_chain_nat
+nft_ct
+nft_masq
+nft_nat
+nft_redir
+
+# Netfilter xt match/target modules (used by kube-proxy iptables rules via nft_compat)
+xt_conntrack
+xt_MASQUERADE
+xt_mark
+xt_comment
+xt_multiport
+xt_nat
+xt_addrtype
+xt_connmark
+xt_REDIRECT
+xt_recent
+xt_statistic
+xt_set
+
+# nft extras (reject, fib — used by kube-proxy nf_tables rules)
+nft_reject
+nft_reject_ipv4
+nft_reject_ipv6
+nft_fib
+nft_fib_ipv4
+nft_fib_ipv6
+
+# Reject targets (used by kube-proxy iptables-restore rules)
+nf_reject_ipv4
+nf_reject_ipv6
+ipt_REJECT
+ip6t_REJECT
+
+# nfacct extension (kube-proxy probes for it)
+xt_nfacct
+
+# Networking — bridge and netfilter (required for K8s pod networking)
+# Load order: llc → stp → bridge → br_netfilter
+llc
+stp
+bridge
+br_netfilter
+veth
+vxlan
+
+# IPVS — useful for kube-proxy IPVS mode and CNI plugins
+ip_vs
+ip_vs_rr
+ip_vs_wrr
+ip_vs_sh

build/config/rpi-kernel-config.fragment

@@ -0,0 +1,69 @@
+# KubeSolo OS — Raspberry Pi kernel config overrides
+# Applied on top of bcm2711_defconfig (Pi 4) or bcm2712_defconfig (Pi 5)
+# These ensure container runtime support is enabled.
+
+# cgroup v2 (mandatory for containerd/runc)
+CONFIG_CGROUPS=y
+CONFIG_CGROUP_CPUACCT=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_PIDS=y
+CONFIG_MEMCG=y
+CONFIG_CGROUP_BPF=y
+CONFIG_CFS_BANDWIDTH=y
+
+# BPF (required for cgroup v2 device control)
+CONFIG_BPF=y
+CONFIG_BPF_SYSCALL=y
+
+# Namespaces (mandatory for containers)
+CONFIG_NAMESPACES=y
+CONFIG_NET_NS=y
+CONFIG_PID_NS=y
+CONFIG_USER_NS=y
+CONFIG_UTS_NS=y
+CONFIG_IPC_NS=y
+
+# Device management
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+
+# Filesystem
+CONFIG_OVERLAY_FS=y
+CONFIG_SQUASHFS=y
+CONFIG_EXT4_FS=y
+CONFIG_VFAT_FS=y
+
+# Networking
+CONFIG_BRIDGE=m
+CONFIG_NETFILTER=y
+CONFIG_NF_CONNTRACK=m
+CONFIG_NF_NAT=m
+CONFIG_NF_TABLES=m
+CONFIG_VETH=m
+CONFIG_VXLAN=m
+
+# Security: AppArmor + Audit
+CONFIG_AUDIT=y
+CONFIG_AUDITSYSCALL=y
+CONFIG_SECURITY=y
+CONFIG_SECURITYFS=y
+CONFIG_SECURITY_NETWORK=y
+CONFIG_SECURITY_APPARMOR=y
+CONFIG_DEFAULT_SECURITY_APPARMOR=y
+
+# Security: seccomp
+CONFIG_SECCOMP=y
+CONFIG_SECCOMP_FILTER=y
+
+# Crypto (image verification)
+CONFIG_CRYPTO_SHA256=y
+
+# Disable unnecessary subsystems for edge appliance
+# CONFIG_SOUND is not set
+# CONFIG_DRM is not set
+# CONFIG_MEDIA_SUPPORT is not set
+# CONFIG_WIRELESS is not set
+# CONFIG_BT is not set
+# CONFIG_NFC is not set

build/config/versions.env

@@ -15,5 +15,28 @@ KUBESOLO_INSTALL_URL=https://get.kubesolo.io
 GRUB_VERSION=2.12
 SYSLINUX_VERSION=6.03
 
+# SHA256 checksums for supply chain verification
+# Populate by running: sha256sum build/cache/<file>
+# Leave empty to skip verification (useful for first fetch)
+TINYCORE_ISO_SHA256=""
+KUBESOLO_SHA256=""
+NETFILTER_TCZ_SHA256=""
+NET_BRIDGING_TCZ_SHA256=""
+IPTABLES_TCZ_SHA256=""
+
+# piCore64 (ARM64 — Raspberry Pi)
+PICORE_VERSION=15.0
+PICORE_ARCH=aarch64
+PICORE_IMAGE=piCore-${PICORE_VERSION}.img.gz
+PICORE_IMAGE_URL=http://www.tinycorelinux.net/${PICORE_VERSION%%.*}.x/${PICORE_ARCH}/releases/RPi/${PICORE_IMAGE}
+
+# Raspberry Pi firmware (boot blobs, DTBs)
+RPI_FIRMWARE_TAG=1.20240529
+RPI_FIRMWARE_URL=https://github.com/raspberrypi/firmware/archive/refs/tags/${RPI_FIRMWARE_TAG}.tar.gz
+
+# Raspberry Pi kernel source
+RPI_KERNEL_BRANCH=rpi-6.6.y
+RPI_KERNEL_REPO=https://github.com/raspberrypi/linux
+
 # Output naming
 OS_NAME=kubesolo-os

build/rootfs/etc/apparmor.d/containerd

@@ -0,0 +1,52 @@
+# AppArmor profile for containerd
+# Start in complain mode to log without blocking
+
+#include <tunables/global>
+
+profile containerd /usr/bin/containerd flags=(complain) {
+  #include <abstractions/base>
+
+  # Binary and shared libraries
+  /usr/bin/containerd                   mr,
+  /usr/lib/**                           mr,
+  /lib/**                               mr,
+
+  # Containerd runtime state
+  /var/lib/containerd/**                rw,
+  /run/containerd/**                    rw,
+
+  # Container image layers and snapshots
+  /var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/** rw,
+
+  # CNI networking
+  /etc/cni/**                           r,
+  /opt/cni/bin/**                       ix,
+
+  # Proc and sys access for containers
+  @{PROC}/**                            r,
+  /sys/**                               r,
+
+  # Device access for containers
+  /dev/**                               rw,
+
+  # Network access
+  network,
+
+  # Container runtime needs broad capabilities
+  capability,
+
+  # Allow executing container runtimes
+  /usr/bin/containerd-shim-runc-v2      ix,
+  /usr/bin/runc                         ix,
+  /usr/sbin/runc                        ix,
+
+  # Temp files
+  /tmp/**                               rw,
+
+  # Log files
+  /var/log/**                           rw,
+
+  # Signal handling for child processes
+  signal,
+  ptrace,
+}

build/rootfs/etc/apparmor.d/kubelet

@@ -0,0 +1,56 @@
+# AppArmor profile for kubesolo (kubelet + control plane)
+# Start in complain mode to log without blocking
+
+#include <tunables/global>
+
+profile kubesolo /usr/bin/kubesolo flags=(complain) {
+  #include <abstractions/base>
+
+  # Binary and shared libraries
+  /usr/bin/kubesolo                     mr,
+  /usr/lib/**                           mr,
+  /lib/**                               mr,
+
+  # KubeSolo state (etcd/SQLite, certificates, manifests)
+  /var/lib/kubesolo/**                  rw,
+
+  # KubeSolo configuration
+  /etc/kubesolo/**                      r,
+
+  # Containerd socket
+  /run/containerd/**                    rw,
+
+  # CNI networking
+  /etc/cni/**                           r,
+  /opt/cni/bin/**                       ix,
+
+  # Proc and sys access
+  @{PROC}/**                            r,
+  /sys/**                               r,
+
+  # Device access
+  /dev/**                               rw,
+
+  # Network access (API server, kubelet, etcd)
+  network,
+
+  # Control plane needs broad capabilities
+  capability,
+
+  # Kubectl and other tools
+  /usr/bin/kubectl                      ix,
+  /usr/local/bin/**                     ix,
+
+  # Temp files
+  /tmp/**                               rw,
+
+  # Log files
+  /var/log/**                           rw,
+
+  # Kubelet needs to manage pods
+  /var/lib/kubelet/**                   rw,
+
+  # Signal handling
+  signal,
+  ptrace,
+}

build/rootfs/etc/sysctl.d/security.conf

@@ -0,0 +1,27 @@
+# Security hardening — applied automatically by 40-sysctl.sh
+# Network: anti-spoofing
+net.ipv4.conf.all.rp_filter = 1
+net.ipv4.conf.default.rp_filter = 1
+# Network: SYN flood protection
+net.ipv4.tcp_syncookies = 1
+# Network: ICMP hardening
+net.ipv4.conf.all.accept_redirects = 0
+net.ipv4.conf.default.accept_redirects = 0
+net.ipv4.conf.all.send_redirects = 0
+net.ipv4.conf.default.send_redirects = 0
+net.ipv4.icmp_echo_ignore_broadcasts = 1
+net.ipv4.icmp_ignore_bogus_error_responses = 1
+net.ipv4.conf.all.log_martians = 1
+# Network: IPv6 hardening
+net.ipv6.conf.all.accept_redirects = 0
+net.ipv6.conf.default.accept_redirects = 0
+net.ipv6.conf.all.accept_ra = 0
+# Network: source routing
+net.ipv4.conf.all.accept_source_route = 0
+net.ipv4.conf.default.accept_source_route = 0
+# Kernel: information disclosure
+kernel.kptr_restrict = 2
+kernel.dmesg_restrict = 1
+kernel.perf_event_paranoid = 3
+# Kernel: core dump safety
+fs.suid_dumpable = 0

build/scripts/build-kernel-arm64.sh

@@ -0,0 +1,158 @@
+#!/bin/bash
+# build-kernel-arm64.sh — Build ARM64 kernel for Raspberry Pi 4/5
+#
+# Uses the official raspberrypi/linux kernel fork with bcm2711_defconfig
+# as the base, overlaid with container-critical config options.
+#
+# Output is cached in $CACHE_DIR/custom-kernel-arm64/ and reused across builds.
+#
+# Requirements:
+#   - gcc-aarch64-linux-gnu (cross-compiler)
+#   - Standard kernel build deps (bc, bison, flex, etc.)
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+CACHE_DIR="${CACHE_DIR:-$PROJECT_ROOT/build/cache}"
+
+# shellcheck source=../config/versions.env
+. "$SCRIPT_DIR/../config/versions.env"
+
+CUSTOM_KERNEL_DIR="$CACHE_DIR/custom-kernel-arm64"
+CUSTOM_IMAGE="$CUSTOM_KERNEL_DIR/Image"
+CUSTOM_MODULES="$CUSTOM_KERNEL_DIR/modules"
+CUSTOM_DTBS="$CUSTOM_KERNEL_DIR/dtbs"
+
+mkdir -p "$CACHE_DIR" "$CUSTOM_KERNEL_DIR"
+
+# --- Skip if already built ---
+if [ -f "$CUSTOM_IMAGE" ] && [ -d "$CUSTOM_MODULES" ]; then
+    echo "==> ARM64 kernel already built (cached)"
+    echo "    Image: $CUSTOM_IMAGE ($(du -h "$CUSTOM_IMAGE" | cut -f1))"
+    exit 0
+fi
+
+# --- Verify cross-compiler ---
+if ! command -v aarch64-linux-gnu-gcc >/dev/null 2>&1; then
+    echo "ERROR: aarch64-linux-gnu-gcc not found"
+    echo "Install: apt-get install gcc-aarch64-linux-gnu"
+    exit 1
+fi
+
+echo "==> Building ARM64 kernel for Raspberry Pi..."
+echo "    Branch: $RPI_KERNEL_BRANCH"
+echo "    Repo:   $RPI_KERNEL_REPO"
+
+# --- Download kernel source ---
+KERNEL_SRC_DIR="$CACHE_DIR/rpi-linux-${RPI_KERNEL_BRANCH}"
+if [ ! -d "$KERNEL_SRC_DIR" ]; then
+    echo "==> Downloading RPi kernel source (shallow clone)..."
+    git clone --depth 1 --branch "$RPI_KERNEL_BRANCH" \
+        "$RPI_KERNEL_REPO" "$KERNEL_SRC_DIR"
+else
+    echo "==> Kernel source already cached"
+fi
+
+# --- Build in /tmp for case-sensitivity ---
+KERNEL_BUILD_DIR="/tmp/kernel-build-arm64"
+rm -rf "$KERNEL_BUILD_DIR"
+cp -a "$KERNEL_SRC_DIR" "$KERNEL_BUILD_DIR"
+
+cd "$KERNEL_BUILD_DIR"
+
+# --- Apply base config (Pi 4 = bcm2711) ---
+echo "==> Applying bcm2711_defconfig..."
+make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- bcm2711_defconfig
+
+# --- Apply container config overrides ---
+CONFIG_FRAGMENT="$PROJECT_ROOT/build/config/rpi-kernel-config.fragment"
+if [ -f "$CONFIG_FRAGMENT" ]; then
+    echo "==> Applying KubeSolo config overrides..."
+    while IFS= read -r line; do
+        # Skip comments and empty lines
+        case "$line" in \#*|"") continue ;; esac
+        key="${line%%=*}"
+        value="${line#*=}"
+        case "$value" in
+            y)   ./scripts/config --enable "$key" ;;
+            m)   ./scripts/config --module "$key" ;;
+            n)   ./scripts/config --disable "${key#CONFIG_}" ;;
+            *)   ./scripts/config --set-str "$key" "$value" ;;
+        esac
+    done < "$CONFIG_FRAGMENT"
+fi
+
+# Handle "is not set" comments as disables
+if [ -f "$CONFIG_FRAGMENT" ]; then
+    while IFS= read -r line; do
+        case "$line" in
+            "# CONFIG_"*" is not set")
+                key=$(echo "$line" | sed -n 's/^# \(CONFIG_[A-Z_]*\) is not set$/\1/p')
+                [ -n "$key" ] && ./scripts/config --disable "${key#CONFIG_}"
+                ;;
+        esac
+    done < "$CONFIG_FRAGMENT"
+fi
+
+# Resolve dependencies
+make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- olddefconfig
+
+# --- Build kernel + modules + DTBs ---
+NPROC=$(nproc 2>/dev/null || echo 4)
+echo ""
+echo "==> Building ARM64 kernel (${NPROC} parallel jobs)..."
+echo "    This may take 20-30 minutes..."
+
+make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j"$NPROC" Image modules dtbs 2>&1
+
+echo "==> ARM64 kernel build complete"
+
+# --- Install to staging ---
+echo "==> Installing Image..."
+cp arch/arm64/boot/Image "$CUSTOM_IMAGE"
+
+echo "==> Installing modules (stripped)..."
+rm -rf "$CUSTOM_MODULES"
+mkdir -p "$CUSTOM_MODULES"
+make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \
+    INSTALL_MOD_STRIP=1 modules_install INSTALL_MOD_PATH="$CUSTOM_MODULES"
+
+# Remove build/source symlinks
+KVER=$(ls "$CUSTOM_MODULES/lib/modules/" | head -1)
+rm -f "$CUSTOM_MODULES/lib/modules/$KVER/build"
+rm -f "$CUSTOM_MODULES/lib/modules/$KVER/source"
+
+# Run depmod
+depmod -a -b "$CUSTOM_MODULES" "$KVER" 2>/dev/null || true
+
+echo "==> Installing Device Tree Blobs..."
+rm -rf "$CUSTOM_DTBS"
+mkdir -p "$CUSTOM_DTBS/overlays"
+# Pi 4 DTBs
+cp arch/arm64/boot/dts/broadcom/bcm2711*.dtb "$CUSTOM_DTBS/" 2>/dev/null || true
+# Pi 5 DTBs
+cp arch/arm64/boot/dts/broadcom/bcm2712*.dtb "$CUSTOM_DTBS/" 2>/dev/null || true
+# Overlays we need
+for overlay in disable-wifi disable-bt; do
+    [ -f "arch/arm64/boot/dts/overlays/${overlay}.dtbo" ] && \
+        cp "arch/arm64/boot/dts/overlays/${overlay}.dtbo" "$CUSTOM_DTBS/overlays/"
+done
+
+# Save config for reference
+cp .config "$CUSTOM_KERNEL_DIR/.config"
+
+# --- Clean up ---
+echo "==> Cleaning kernel build directory..."
+cd /
+rm -rf "$KERNEL_BUILD_DIR"
+
+# --- Summary ---
+echo ""
+echo "==> ARM64 kernel build complete:"
+echo "    Image:        $CUSTOM_IMAGE ($(du -h "$CUSTOM_IMAGE" | cut -f1))"
+echo "    Kernel ver:   $KVER"
+MOD_COUNT=$(find "$CUSTOM_MODULES/lib/modules/$KVER" -name '*.ko*' 2>/dev/null | wc -l)
+echo "    Modules:      $MOD_COUNT"
+echo "    Modules size: $(du -sh "$CUSTOM_MODULES/lib/modules/$KVER" 2>/dev/null | cut -f1)"
+echo "    DTBs:         $(ls "$CUSTOM_DTBS"/*.dtb 2>/dev/null | wc -l)"
+echo ""

build/scripts/build-kernel.sh

@@ -96,6 +96,17 @@ echo "==> Enabling required kernel configs..."
 ./scripts/config --enable CONFIG_MEMCG
 ./scripts/config --enable CONFIG_CFS_BANDWIDTH
 
+# Security: AppArmor LSM + Audit subsystem
+echo "==> Enabling AppArmor + Audit kernel configs..."
+./scripts/config --enable CONFIG_AUDIT
+./scripts/config --enable CONFIG_AUDITSYSCALL
+./scripts/config --enable CONFIG_SECURITY
+./scripts/config --enable CONFIG_SECURITYFS
+./scripts/config --enable CONFIG_SECURITY_NETWORK
+./scripts/config --enable CONFIG_SECURITY_APPARMOR
+./scripts/config --set-str CONFIG_LSM "lockdown,yama,apparmor"
+./scripts/config --set-str CONFIG_DEFAULT_SECURITY "apparmor"
+
 # --- Strip unnecessary subsystems for smallest footprint ---
 # This is a headless K8s edge appliance — no sound, GPU, wireless, etc.
 echo "==> Disabling unnecessary subsystems for minimal footprint..."

build/scripts/create-rpi-image.sh

@@ -0,0 +1,203 @@
+#!/bin/bash
+# create-rpi-image.sh — Create a raw disk image for Raspberry Pi SD card
+#
+# Partition layout (GPT):
+#   Part 1: Boot Control  (16 MB, FAT32, label KSOLOCTL) — autoboot.txt only
+#   Part 2: Boot A        (256 MB, FAT32, label KSOLOA)  — firmware + kernel + DTBs + initramfs
+#   Part 3: Boot B        (256 MB, FAT32, label KSOLOB)  — same as Boot A (initially identical)
+#   Part 4: Data          (remaining of 2GB, ext4, label KSOLODATA)
+#
+# The RPi uses autoboot.txt in the control partition to implement A/B boot
+# via the tryboot mechanism (tryboot_a_b=1). Normal boot → partition 2 (Boot A),
+# tryboot → partition 3 (Boot B).
+#
+# Usage: build/scripts/create-rpi-image.sh
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+
+# shellcheck source=../config/versions.env
+. "$SCRIPT_DIR/../config/versions.env"
+
+ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"
+OUTPUT_DIR="${OUTPUT_DIR:-$PROJECT_ROOT/output}"
+CACHE_DIR="${CACHE_DIR:-$PROJECT_ROOT/build/cache}"
+VERSION="$(cat "$PROJECT_ROOT/VERSION")"
+
+IMG_OUTPUT="$OUTPUT_DIR/${OS_NAME}-${VERSION}.rpi.img"
+IMG_SIZE_MB="${IMG_SIZE_MB:-2048}"  # 2 GB default
+
+# ARM64 kernel (Image format, not bzImage)
+KERNEL="${CACHE_DIR}/custom-kernel-arm64/Image"
+INITRAMFS="${ROOTFS_DIR}/kubesolo-os.gz"
+RPI_FIRMWARE_DIR="${CACHE_DIR}/rpi-firmware"
+
+echo "==> Creating ${IMG_SIZE_MB}MB Raspberry Pi disk image..."
+
+# --- Verify required files ---
+MISSING=0
+for f in "$KERNEL" "$INITRAMFS"; do
+    if [ ! -f "$f" ]; then
+        echo "ERROR: Missing $f"
+        MISSING=1
+    fi
+done
+
+if [ ! -d "$RPI_FIRMWARE_DIR" ]; then
+    echo "ERROR: Missing RPi firmware directory: $RPI_FIRMWARE_DIR"
+    echo "  Run 'make fetch' to download firmware blobs."
+    MISSING=1
+fi
+
+if [ "$MISSING" = "1" ]; then
+    echo ""
+    echo "Required files:"
+    echo "  Kernel:    $KERNEL (run 'make kernel-arm64')"
+    echo "  Initramfs: $INITRAMFS (run 'make initramfs')"
+    echo "  Firmware:  $RPI_FIRMWARE_DIR/ (run 'make fetch')"
+    exit 1
+fi
+
+mkdir -p "$OUTPUT_DIR"
+
+# --- Create sparse image ---
+dd if=/dev/zero of="$IMG_OUTPUT" bs=1M count=0 seek="$IMG_SIZE_MB" 2>/dev/null
+
+# --- Partition table (GPT) ---
+# Part 1: Boot Control  16 MB FAT32
+# Part 2: Boot A       256 MB FAT32
+# Part 3: Boot B       256 MB FAT32
+# Part 4: Data         remaining ext4
+sfdisk "$IMG_OUTPUT" << EOF
+label: gpt
+
+# Boot Control partition: 16 MB
+start=2048, size=32768, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, name="BootCtl"
+# Boot A partition: 256 MB
+size=524288, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, name="BootA"
+# Boot B partition: 256 MB
+size=524288, type=EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, name="BootB"
+# Data partition: remaining
+type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, name="Data"
+EOF
+
+# --- Set up loop device ---
+LOOP=$(losetup --show -fP "$IMG_OUTPUT")
+echo "==> Loop device: $LOOP"
+
+MNT_CTL=$(mktemp -d)
+MNT_BOOTA=$(mktemp -d)
+MNT_BOOTB=$(mktemp -d)
+MNT_DATA=$(mktemp -d)
+
+cleanup() {
+    umount "$MNT_CTL" 2>/dev/null || true
+    umount "$MNT_BOOTA" 2>/dev/null || true
+    umount "$MNT_BOOTB" 2>/dev/null || true
+    umount "$MNT_DATA" 2>/dev/null || true
+    losetup -d "$LOOP" 2>/dev/null || true
+    rm -rf "$MNT_CTL" "$MNT_BOOTA" "$MNT_BOOTB" "$MNT_DATA" 2>/dev/null || true
+}
+trap cleanup EXIT
+
+# --- Format partitions ---
+mkfs.vfat -F 32 -n KSOLOCTL "${LOOP}p1"
+mkfs.vfat -F 32 -n KSOLOA "${LOOP}p2"
+mkfs.vfat -F 32 -n KSOLOB "${LOOP}p3"
+mkfs.ext4 -q -L KSOLODATA "${LOOP}p4"
+
+# --- Mount all partitions ---
+mount "${LOOP}p1" "$MNT_CTL"
+mount "${LOOP}p2" "$MNT_BOOTA"
+mount "${LOOP}p3" "$MNT_BOOTB"
+mount "${LOOP}p4" "$MNT_DATA"
+
+# --- Boot Control Partition (KSOLOCTL) ---
+echo "    Writing autoboot.txt..."
+cat > "$MNT_CTL/autoboot.txt" << 'AUTOBOOT'
+[all]
+tryboot_a_b=1
+boot_partition=2
+[tryboot]
+boot_partition=3
+AUTOBOOT
+
+# --- Helper: populate a boot partition ---
+populate_boot_partition() {
+    local MNT="$1"
+    local LABEL="$2"
+
+    echo "    Populating $LABEL..."
+
+    # config.txt — Raspberry Pi boot configuration
+    cat > "$MNT/config.txt" << 'CFGTXT'
+arm_64bit=1
+kernel=kernel8.img
+initramfs kubesolo-os.gz followkernel
+enable_uart=1
+gpu_mem=16
+dtoverlay=disable-wifi
+dtoverlay=disable-bt
+CFGTXT
+
+    # cmdline.txt — kernel command line
+    # Note: must be a single line
+    echo "console=serial0,115200 console=tty1 kubesolo.data=LABEL=KSOLODATA quiet" > "$MNT/cmdline.txt"
+
+    # Copy kernel as kernel8.img (RPi 3/4/5 ARM64 convention)
+    cp "$KERNEL" "$MNT/kernel8.img"
+
+    # Copy initramfs
+    cp "$INITRAMFS" "$MNT/kubesolo-os.gz"
+
+    # Copy firmware blobs (start*.elf, fixup*.dat)
+    if ls "$RPI_FIRMWARE_DIR"/start*.elf 1>/dev/null 2>&1; then
+        cp "$RPI_FIRMWARE_DIR"/start*.elf "$MNT/"
+    fi
+    if ls "$RPI_FIRMWARE_DIR"/fixup*.dat 1>/dev/null 2>&1; then
+        cp "$RPI_FIRMWARE_DIR"/fixup*.dat "$MNT/"
+    fi
+    if [ -f "$RPI_FIRMWARE_DIR/bootcode.bin" ]; then
+        cp "$RPI_FIRMWARE_DIR/bootcode.bin" "$MNT/"
+    fi
+
+    # Copy DTB overlays
+    if [ -d "$RPI_FIRMWARE_DIR/overlays" ]; then
+        cp -r "$RPI_FIRMWARE_DIR/overlays" "$MNT/"
+    fi
+
+    # Copy base DTBs (bcm2710-*, bcm2711-*, bcm2712-*)
+    if ls "$RPI_FIRMWARE_DIR"/bcm27*.dtb 1>/dev/null 2>&1; then
+        cp "$RPI_FIRMWARE_DIR"/bcm27*.dtb "$MNT/"
+    fi
+
+    # Write version marker
+    echo "$VERSION" > "$MNT/version.txt"
+}
+
+# --- Boot A Partition (KSOLOA) ---
+populate_boot_partition "$MNT_BOOTA" "Boot A (KSOLOA)"
+
+# --- Boot B Partition (KSOLOB, initially identical) ---
+populate_boot_partition "$MNT_BOOTB" "Boot B (KSOLOB)"
+
+# --- Data Partition (KSOLODATA) ---
+echo "    Preparing data partition..."
+for dir in kubesolo containerd etc-kubesolo log usr-local network images; do
+    mkdir -p "$MNT_DATA/$dir"
+done
+
+sync
+
+echo ""
+echo "==> Raspberry Pi disk image created: $IMG_OUTPUT"
+echo "    Size: $(du -h "$IMG_OUTPUT" | cut -f1)"
+echo "    Part 1 (KSOLOCTL):  Boot control (autoboot.txt)"
+echo "    Part 2 (KSOLOA):    Boot A — firmware + kernel + initramfs"
+echo "    Part 3 (KSOLOB):    Boot B — firmware + kernel + initramfs"
+echo "    Part 4 (KSOLODATA): Persistent K8s state"
+echo ""
+echo "Write to SD card with:"
+echo "    sudo dd if=$IMG_OUTPUT of=/dev/sdX bs=4M status=progress"
+echo ""

build/scripts/extract-core.sh

@@ -10,6 +10,94 @@ ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"
 # shellcheck source=../config/versions.env
 . "$SCRIPT_DIR/../config/versions.env"
 
+EXTRACT_ARCH="${TARGET_ARCH:-amd64}"
+
+# Clean previous rootfs
+rm -rf "$ROOTFS_DIR"
+mkdir -p "$ROOTFS_DIR"
+
+# =========================================================================
+# ARM64: piCore64 .img.gz extraction (SD card image, not ISO)
+# =========================================================================
+if [ "$EXTRACT_ARCH" = "arm64" ]; then
+    PICORE_IMG="$CACHE_DIR/$PICORE_IMAGE"
+    if [ ! -f "$PICORE_IMG" ]; then
+        echo "ERROR: piCore64 image not found: $PICORE_IMG"
+        echo "Run 'TARGET_ARCH=arm64 make fetch' first."
+        exit 1
+    fi
+
+    echo "==> Extracting piCore64 image: $PICORE_IMG"
+
+    # Decompress .img.gz to raw image
+    PICORE_RAW="$CACHE_DIR/piCore-${PICORE_VERSION}.img"
+    if [ ! -f "$PICORE_RAW" ]; then
+        echo "    Decompressing..."
+        gunzip -k "$PICORE_IMG" 2>/dev/null || \
+            zcat "$PICORE_IMG" > "$PICORE_RAW"
+    fi
+
+    # Mount the piCore rootfs partition (partition 2 in the SD image)
+    # Use losetup to find the partition offset
+    IMG_MNT=$(mktemp -d)
+    echo "    Mounting piCore rootfs partition..."
+
+    # Get partition 2 offset (piCore layout: boot=p1, rootfs=p2)
+    OFFSET=$(fdisk -l "$PICORE_RAW" 2>/dev/null | awk '/^.*img2/{print $2}')
+    if [ -z "$OFFSET" ]; then
+        # Fallback: try sfdisk
+        OFFSET=$(sfdisk -d "$PICORE_RAW" 2>/dev/null | awk -F'[=,]' '/start=/{print $2; exit}' | tr -d ' ')
+    fi
+    if [ -z "$OFFSET" ]; then
+        echo "ERROR: Could not determine partition offset in piCore image"
+        fdisk -l "$PICORE_RAW" || true
+        exit 1
+    fi
+
+    BYTE_OFFSET=$((OFFSET * 512))
+    mount -o loop,ro,offset="$BYTE_OFFSET" "$PICORE_RAW" "$IMG_MNT" || {
+        echo "ERROR: Failed to mount piCore rootfs (need root for losetup)"
+        exit 1
+    }
+
+    # Find initramfs in the piCore rootfs
+    COREGZ=""
+    for f in "$IMG_MNT"/boot/corepure64.gz "$IMG_MNT"/boot/core.gz "$IMG_MNT"/*.gz; do
+        [ -f "$f" ] && COREGZ="$f" && break
+    done
+
+    if [ -z "$COREGZ" ]; then
+        echo "ERROR: Could not find initramfs in piCore image"
+        echo "Contents:"
+        ls -la "$IMG_MNT"/
+        ls -la "$IMG_MNT"/boot/ 2>/dev/null || true
+        umount "$IMG_MNT" 2>/dev/null || true
+        exit 1
+    fi
+
+    echo "==> Found initramfs: $COREGZ"
+
+    # Extract initramfs
+    mkdir -p "$ROOTFS_DIR/rootfs"
+    cd "$ROOTFS_DIR/rootfs"
+    zcat "$COREGZ" | cpio -idm 2>/dev/null
+
+    # Note: ARM64 kernel comes from build-kernel-arm64.sh, not from piCore
+    # We only use piCore for the BusyBox userland
+
+    cd "$PROJECT_ROOT"
+    umount "$IMG_MNT" 2>/dev/null || true
+    rm -rf "$IMG_MNT"
+
+    echo "==> ARM64 rootfs extracted: $ROOTFS_DIR/rootfs"
+    echo "    Size: $(du -sh "$ROOTFS_DIR/rootfs" | cut -f1)"
+    echo "==> Extract complete (ARM64). Kernel will come from build-kernel-arm64.sh"
+    exit 0
+fi
+
+# =========================================================================
+# x86_64: Tiny Core ISO extraction
+# =========================================================================
 TC_ISO="$CACHE_DIR/$TINYCORE_ISO"
 ISO_MNT="$ROOTFS_DIR/iso-mount"
 
@@ -19,9 +107,7 @@ if [ ! -f "$TC_ISO" ]; then
     exit 1
 fi
 
-# Clean previous rootfs
+mkdir -p "$ISO_MNT"
-rm -rf "$ROOTFS_DIR"
-mkdir -p "$ROOTFS_DIR" "$ISO_MNT"
 
 # --- Mount ISO and extract kernel + initramfs ---
 echo "==> Mounting ISO: $TC_ISO"

build/scripts/fetch-components.sh

@@ -10,9 +10,56 @@ CACHE_DIR="${CACHE_DIR:-$PROJECT_ROOT/build/cache}"
 # shellcheck source=../config/versions.env
 . "$SCRIPT_DIR/../config/versions.env"
 
+# Verify SHA256 checksum of a downloaded file
+verify_checksum() {
+    local file="$1" expected="$2" name="$3"
+    # Skip if no expected checksum provided
+    [ -z "$expected" ] && return 0
+    local actual
+    actual=$(sha256sum "$file" | awk '{print $1}')
+    if [ "$actual" = "$expected" ]; then
+        echo "    Checksum OK: $name"
+        return 0
+    else
+        echo "ERROR: Checksum mismatch for $name"
+        echo "  Expected: $expected"
+        echo "  Got:      $actual"
+        rm -f "$file"
+        return 1
+    fi
+}
+
 mkdir -p "$CACHE_DIR"
 
-# --- Tiny Core Linux ISO ---
+# Detect target architecture
+FETCH_ARCH="${TARGET_ARCH:-amd64}"
+
+# --- ARM64: piCore64 image instead of x86_64 ISO ---
+if [ "$FETCH_ARCH" = "arm64" ]; then
+    PICORE_IMG="$CACHE_DIR/$PICORE_IMAGE"
+    if [ -f "$PICORE_IMG" ]; then
+        echo "==> piCore64 image already cached: $PICORE_IMG"
+    else
+        echo "==> Downloading piCore64 ${PICORE_VERSION} (${PICORE_ARCH})..."
+        echo "    URL: $PICORE_IMAGE_URL"
+        wget -q --show-progress -O "$PICORE_IMG" "$PICORE_IMAGE_URL" 2>/dev/null || \
+            curl -fSL "$PICORE_IMAGE_URL" -o "$PICORE_IMG"
+        echo "==> Downloaded: $PICORE_IMG ($(du -h "$PICORE_IMG" | cut -f1))"
+    fi
+
+    # Also fetch RPi firmware
+    echo "==> Fetching RPi firmware..."
+    "$SCRIPT_DIR/fetch-rpi-firmware.sh"
+
+    # Skip x86_64 ISO and TCZ downloads for ARM64
+    echo ""
+    echo "==> ARM64 fetch complete."
+    echo "==> Component cache:"
+    ls -lh "$CACHE_DIR"/ 2>/dev/null || true
+    exit 0
+fi
+
+# --- x86_64: Tiny Core Linux ISO ---
 TC_ISO="$CACHE_DIR/$TINYCORE_ISO"
 TC_URL="${TINYCORE_MIRROR}/${TINYCORE_VERSION%%.*}.x/${TINYCORE_ARCH}/release/${TINYCORE_ISO}"
 
@@ -28,6 +75,7 @@ else
         wget -q --show-progress -O "$TC_ISO" "$TC_URL_ALT"
     }
     echo "==> Downloaded: $TC_ISO ($(du -h "$TC_ISO" | cut -f1))"
+    verify_checksum "$TC_ISO" "$TINYCORE_ISO_SHA256" "Tiny Core ISO"
 fi
 
 # --- KubeSolo ---
@@ -88,6 +136,7 @@ else
     rm -rf "$TEMP_DIR"
 
     echo "==> KubeSolo binary: $KUBESOLO_BIN ($(du -h "$KUBESOLO_BIN" | cut -f1))"
+    verify_checksum "$KUBESOLO_BIN" "$KUBESOLO_SHA256" "KubeSolo binary"
 fi
 
 # --- Tiny Core kernel module extensions (netfilter, iptables) ---
@@ -114,6 +163,7 @@ else
     if wget -q --show-progress -O "$NETFILTER_TCZ" "$NETFILTER_TCZ_URL" 2>/dev/null || \
        curl -fSL "$NETFILTER_TCZ_URL" -o "$NETFILTER_TCZ" 2>/dev/null; then
         echo "==> Downloaded: $NETFILTER_TCZ ($(du -h "$NETFILTER_TCZ" | cut -f1))"
+        verify_checksum "$NETFILTER_TCZ" "$NETFILTER_TCZ_SHA256" "netfilter TCZ"
     else
         echo "WARN: Failed to download netfilter modules. kube-proxy may not work."
         rm -f "$NETFILTER_TCZ"
@@ -131,6 +181,7 @@ else
     if wget -q --show-progress -O "$NET_BRIDGING_TCZ" "$NET_BRIDGING_TCZ_URL" 2>/dev/null || \
        curl -fSL "$NET_BRIDGING_TCZ_URL" -o "$NET_BRIDGING_TCZ" 2>/dev/null; then
         echo "==> Downloaded: $NET_BRIDGING_TCZ ($(du -h "$NET_BRIDGING_TCZ" | cut -f1))"
+        verify_checksum "$NET_BRIDGING_TCZ" "$NET_BRIDGING_TCZ_SHA256" "net-bridging TCZ"
     else
         echo "WARN: Failed to download net-bridging modules. CNI bridge may not work."
         rm -f "$NET_BRIDGING_TCZ"
@@ -148,6 +199,7 @@ else
     if wget -q --show-progress -O "$IPTABLES_TCZ" "$IPTABLES_TCZ_URL" 2>/dev/null || \
        curl -fSL "$IPTABLES_TCZ_URL" -o "$IPTABLES_TCZ" 2>/dev/null; then
         echo "==> Downloaded: $IPTABLES_TCZ ($(du -h "$IPTABLES_TCZ" | cut -f1))"
+        verify_checksum "$IPTABLES_TCZ" "$IPTABLES_TCZ_SHA256" "iptables TCZ"
     else
         echo "WARN: Failed to download iptables. KubeSolo bundles its own but this is a fallback."
         rm -f "$IPTABLES_TCZ"

build/scripts/fetch-rpi-firmware.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+# fetch-rpi-firmware.sh — Download Raspberry Pi firmware blobs for boot
+#
+# Downloads firmware from the official raspberrypi/firmware GitHub repository.
+# Extracts only the boot files needed: start*.elf, fixup*.dat, DTBs, bootcode.bin.
+#
+# Output: build/cache/rpi-firmware/ containing all required boot files.
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+CACHE_DIR="${CACHE_DIR:-$PROJECT_ROOT/build/cache}"
+
+# shellcheck source=../config/versions.env
+. "$SCRIPT_DIR/../config/versions.env"
+
+RPI_FW_DIR="$CACHE_DIR/rpi-firmware"
+RPI_FW_ARCHIVE="$CACHE_DIR/rpi-firmware-${RPI_FIRMWARE_TAG}.tar.gz"
+
+# --- Skip if already fetched ---
+if [ -d "$RPI_FW_DIR" ] && [ -f "$RPI_FW_DIR/start4.elf" ]; then
+    echo "==> RPi firmware already cached: $RPI_FW_DIR"
+    echo "    Files: $(ls "$RPI_FW_DIR" | wc -l)"
+    exit 0
+fi
+
+echo "==> Downloading Raspberry Pi firmware (tag: ${RPI_FIRMWARE_TAG})..."
+mkdir -p "$CACHE_DIR" "$RPI_FW_DIR"
+
+# --- Download firmware archive ---
+if [ ! -f "$RPI_FW_ARCHIVE" ]; then
+    echo "    URL: $RPI_FIRMWARE_URL"
+    wget -q --show-progress -O "$RPI_FW_ARCHIVE" "$RPI_FIRMWARE_URL" 2>/dev/null || \
+        curl -fSL "$RPI_FIRMWARE_URL" -o "$RPI_FW_ARCHIVE"
+    echo "    Downloaded: $(du -h "$RPI_FW_ARCHIVE" | cut -f1)"
+else
+    echo "    Archive already cached: $(du -h "$RPI_FW_ARCHIVE" | cut -f1)"
+fi
+
+# --- Extract boot files only ---
+echo "==> Extracting boot files..."
+TEMP_DIR=$(mktemp -d)
+trap "rm -rf '$TEMP_DIR'" EXIT
+
+# Extract only the boot/ directory from the archive
+# Archive structure: firmware-<tag>/boot/...
+tar -xzf "$RPI_FW_ARCHIVE" -C "$TEMP_DIR" --strip-components=1 '*/boot/'
+
+BOOT_SRC="$TEMP_DIR/boot"
+if [ ! -d "$BOOT_SRC" ]; then
+    echo "ERROR: boot/ directory not found in firmware archive"
+    ls -la "$TEMP_DIR"/
+    exit 1
+fi
+
+# Copy GPU firmware (required for boot)
+for f in "$BOOT_SRC"/start*.elf "$BOOT_SRC"/fixup*.dat; do
+    [ -f "$f" ] && cp "$f" "$RPI_FW_DIR/"
+done
+
+# Copy bootcode.bin (first-stage boot for Pi 3 and older)
+[ -f "$BOOT_SRC/bootcode.bin" ] && cp "$BOOT_SRC/bootcode.bin" "$RPI_FW_DIR/"
+
+# Copy Device Tree Blobs for Pi 4 + Pi 5
+for dtb in bcm2711-rpi-4-b.dtb bcm2711-rpi-400.dtb bcm2711-rpi-cm4.dtb \
+           bcm2712-rpi-5-b.dtb bcm2712d0-rpi-5-b.dtb; do
+    [ -f "$BOOT_SRC/$dtb" ] && cp "$BOOT_SRC/$dtb" "$RPI_FW_DIR/"
+done
+
+# Copy overlays directory (needed for config.txt dtoverlay= directives)
+if [ -d "$BOOT_SRC/overlays" ]; then
+    mkdir -p "$RPI_FW_DIR/overlays"
+    # Only copy overlays we actually use (disable-wifi, disable-bt)
+    for overlay in disable-wifi.dtbo disable-bt.dtbo; do
+        [ -f "$BOOT_SRC/overlays/$overlay" ] && \
+            cp "$BOOT_SRC/overlays/$overlay" "$RPI_FW_DIR/overlays/"
+    done
+fi
+
+trap - EXIT
+rm -rf "$TEMP_DIR"
+
+# --- Summary ---
+echo ""
+echo "==> RPi firmware extracted to: $RPI_FW_DIR"
+echo "    Files:"
+ls -1 "$RPI_FW_DIR" | head -20
+echo "    Total size: $(du -sh "$RPI_FW_DIR" | cut -f1)"

build/scripts/inject-kubesolo.sh

@@ -8,6 +8,16 @@ CACHE_DIR="${CACHE_DIR:-$PROJECT_ROOT/build/cache}"
 ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"
 ROOTFS="$ROOTFS_DIR/rootfs"
 VERSION="$(cat "$PROJECT_ROOT/VERSION")"
+INJECT_ARCH="${TARGET_ARCH:-amd64}"
+
+# Architecture-specific paths
+if [ "$INJECT_ARCH" = "arm64" ]; then
+    LIB_ARCH="aarch64-linux-gnu"
+    LD_SO="/lib/ld-linux-aarch64.so.1"
+else
+    LIB_ARCH="x86_64-linux-gnu"
+    LD_SO="/lib64/ld-linux-x86-64.so.2"
+fi
 
 if [ ! -d "$ROOTFS" ]; then
     echo "ERROR: Rootfs not found: $ROOTFS"
@@ -90,8 +100,13 @@ fi
 # --- 3. Custom kernel or TCZ kernel modules ---
 # If a custom kernel was built (with CONFIG_CGROUP_BPF=y), use it.
 # Otherwise fall back to TCZ-extracted modules with manual modules.dep.
+if [ "$INJECT_ARCH" = "arm64" ]; then
+    CUSTOM_KERNEL_DIR="$CACHE_DIR/custom-kernel-arm64"
+    CUSTOM_VMLINUZ="$CUSTOM_KERNEL_DIR/Image"
+else
     CUSTOM_KERNEL_DIR="$CACHE_DIR/custom-kernel"
     CUSTOM_VMLINUZ="$CUSTOM_KERNEL_DIR/vmlinuz"
+fi
 CUSTOM_MODULES="$CUSTOM_KERNEL_DIR/modules"
 
 # Detect kernel version from rootfs
@@ -131,7 +146,11 @@ if [ -f "$CUSTOM_VMLINUZ" ] && [ -d "$CUSTOM_MODULES/lib/modules/$KVER" ]; then
     done
 
     # Use modprobe --show-depends to resolve each module + its transitive deps
+    if [ "$INJECT_ARCH" = "arm64" ]; then
+        MODULES_LIST="$PROJECT_ROOT/build/config/modules-arm64.list"
+    else
         MODULES_LIST="$PROJECT_ROOT/build/config/modules.list"
+    fi
     NEEDED_MODS=$(mktemp)
     while IFS= read -r mod; do
         # Skip comments and blank lines
@@ -291,21 +310,22 @@ if [ -f /usr/sbin/xtables-nft-multi ]; then
         ln -sf xtables-nft-multi "$ROOTFS/usr/sbin/$cmd"
     done
 
-    # Copy required shared libraries
+    # Copy required shared libraries (architecture-aware paths)
-    mkdir -p "$ROOTFS/usr/lib/x86_64-linux-gnu" "$ROOTFS/lib/x86_64-linux-gnu" "$ROOTFS/lib64"
+    mkdir -p "$ROOTFS/usr/lib/$LIB_ARCH" "$ROOTFS/lib/$LIB_ARCH"
+    [ "$INJECT_ARCH" != "arm64" ] && mkdir -p "$ROOTFS/lib64"
     for lib in \
-        /lib/x86_64-linux-gnu/libxtables.so.12* \
+        "/lib/$LIB_ARCH/libxtables.so.12"* \
-        /lib/x86_64-linux-gnu/libmnl.so.0* \
+        "/lib/$LIB_ARCH/libmnl.so.0"* \
-        /lib/x86_64-linux-gnu/libnftnl.so.11* \
+        "/lib/$LIB_ARCH/libnftnl.so.11"* \
-        /lib/x86_64-linux-gnu/libc.so.6 \
+        "/lib/$LIB_ARCH/libc.so.6" \
-        /lib64/ld-linux-x86-64.so.2; do
+        "$LD_SO"; do
         [ -e "$lib" ] && cp -aL "$lib" "$ROOTFS${lib}" 2>/dev/null || true
     done
 
     # Copy xtables modules directory (match extensions)
-    if [ -d /usr/lib/x86_64-linux-gnu/xtables ]; then
+    if [ -d "/usr/lib/$LIB_ARCH/xtables" ]; then
-        mkdir -p "$ROOTFS/usr/lib/x86_64-linux-gnu/xtables"
+        mkdir -p "$ROOTFS/usr/lib/$LIB_ARCH/xtables"
-        cp -a /usr/lib/x86_64-linux-gnu/xtables/*.so "$ROOTFS/usr/lib/x86_64-linux-gnu/xtables/" 2>/dev/null || true
+        cp -a "/usr/lib/$LIB_ARCH/xtables/"*.so "$ROOTFS/usr/lib/$LIB_ARCH/xtables/" 2>/dev/null || true
     fi
 
     echo "    Installed iptables-nft (xtables-nft-multi) + shared libs"
@@ -314,11 +334,16 @@ else
 fi
 
 # Kernel modules list (for init to load at boot)
+if [ "$INJECT_ARCH" = "arm64" ]; then
+    cp "$PROJECT_ROOT/build/config/modules-arm64.list" "$ROOTFS/usr/lib/kubesolo-os/modules.list"
+else
     cp "$PROJECT_ROOT/build/config/modules.list" "$ROOTFS/usr/lib/kubesolo-os/modules.list"
+fi
 
 # --- 4. Sysctl config ---
 mkdir -p "$ROOTFS/etc/sysctl.d"
 cp "$PROJECT_ROOT/build/rootfs/etc/sysctl.d/k8s.conf" "$ROOTFS/etc/sysctl.d/k8s.conf"
+cp "$PROJECT_ROOT/build/rootfs/etc/sysctl.d/security.conf" "$ROOTFS/etc/sysctl.d/security.conf"
 
 # --- 5. OS metadata ---
 echo "$VERSION" > "$ROOTFS/etc/kubesolo-os-version"
@@ -362,7 +387,35 @@ else
     echo "    WARN: No CA certificates found in builder — TLS verification will fail"
 fi
 
-# --- 9. Ensure /etc/hosts and /etc/resolv.conf exist ---
+# --- 9. AppArmor parser + profiles ---
+echo "    Installing AppArmor..."
+if [ -f /usr/sbin/apparmor_parser ]; then
+    mkdir -p "$ROOTFS/usr/sbin"
+    cp /usr/sbin/apparmor_parser "$ROOTFS/usr/sbin/apparmor_parser"
+    chmod +x "$ROOTFS/usr/sbin/apparmor_parser"
+
+    # Copy shared libraries required by apparmor_parser
+    for lib in "/lib/$LIB_ARCH/libapparmor.so.1"*; do
+        [ -e "$lib" ] && cp -aL "$lib" "$ROOTFS${lib}" 2>/dev/null || true
+    done
+
+    echo "    Installed apparmor_parser + shared libs"
+else
+    echo "    WARN: apparmor_parser not found in builder (install apparmor package)"
+fi
+
+# Copy AppArmor profiles
+APPARMOR_PROFILES="$PROJECT_ROOT/build/rootfs/etc/apparmor.d"
+if [ -d "$APPARMOR_PROFILES" ]; then
+    mkdir -p "$ROOTFS/etc/apparmor.d"
+    cp "$APPARMOR_PROFILES"/* "$ROOTFS/etc/apparmor.d/" 2>/dev/null || true
+    PROFILE_COUNT=$(ls "$ROOTFS/etc/apparmor.d/" 2>/dev/null | wc -l)
+    echo "    Installed $PROFILE_COUNT AppArmor profiles"
+else
+    echo "    WARN: No AppArmor profiles found at $APPARMOR_PROFILES"
+fi
+
+# --- 10. Ensure /etc/hosts and /etc/resolv.conf exist ---
 if [ ! -f "$ROOTFS/etc/hosts" ]; then
     cat > "$ROOTFS/etc/hosts" << EOF
 127.0.0.1 localhost

hack/dev-vm-arm64.sh

@@ -0,0 +1,100 @@
+#!/bin/bash
+# dev-vm-arm64.sh — Launch ARM64 QEMU VM for development
+#
+# Uses qemu-system-aarch64 with -machine virt to emulate an ARM64 system.
+# This is useful for testing ARM64/RPi builds on x86_64 hosts.
+#
+# Usage:
+#   ./hack/dev-vm-arm64.sh                           # Use default kernel + initramfs
+#   ./hack/dev-vm-arm64.sh <kernel> <initramfs>      # Specify custom paths
+#   ./hack/dev-vm-arm64.sh --debug                   # Enable debug logging
+#   ./hack/dev-vm-arm64.sh --shell                   # Drop to emergency shell
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+VMLINUZ=""
+INITRD=""
+EXTRA_APPEND=""
+
+# Parse arguments
+for arg in "$@"; do
+    case "$arg" in
+        --shell)   EXTRA_APPEND="$EXTRA_APPEND kubesolo.shell" ;;
+        --debug)   EXTRA_APPEND="$EXTRA_APPEND kubesolo.debug" ;;
+        *)
+            if [ -z "$VMLINUZ" ]; then
+                VMLINUZ="$arg"
+            elif [ -z "$INITRD" ]; then
+                INITRD="$arg"
+            fi
+            ;;
+    esac
+done
+
+# Defaults
+VMLINUZ="${VMLINUZ:-$PROJECT_ROOT/build/cache/custom-kernel-arm64/Image}"
+INITRD="${INITRD:-$PROJECT_ROOT/build/rootfs-work/kubesolo-os.gz}"
+
+# Verify files exist
+if [ ! -f "$VMLINUZ" ]; then
+    echo "ERROR: Kernel not found: $VMLINUZ"
+    echo "  Run 'make kernel-arm64' to build the ARM64 kernel."
+    exit 1
+fi
+if [ ! -f "$INITRD" ]; then
+    echo "ERROR: Initrd not found: $INITRD"
+    echo "  Run 'make initramfs' to build the initramfs."
+    exit 1
+fi
+
+# Find mkfs.ext4
+MKFS_EXT4=""
+if command -v mkfs.ext4 >/dev/null 2>&1; then
+    MKFS_EXT4="mkfs.ext4"
+elif [ -x "/opt/homebrew/opt/e2fsprogs/sbin/mkfs.ext4" ]; then
+    MKFS_EXT4="/opt/homebrew/opt/e2fsprogs/sbin/mkfs.ext4"
+elif [ -x "/usr/local/opt/e2fsprogs/sbin/mkfs.ext4" ]; then
+    MKFS_EXT4="/usr/local/opt/e2fsprogs/sbin/mkfs.ext4"
+fi
+
+if [ -z "$MKFS_EXT4" ]; then
+    echo "ERROR: mkfs.ext4 not found. Install e2fsprogs:"
+    if [ "$(uname)" = "Darwin" ]; then
+        echo "  brew install e2fsprogs"
+    else
+        echo "  apt install e2fsprogs   # Debian/Ubuntu"
+        echo "  dnf install e2fsprogs   # Fedora/RHEL"
+    fi
+    exit 1
+fi
+
+# Create data disk
+DATA_DISK="$(mktemp /tmp/kubesolo-arm64-data-XXXXXX).img"
+dd if=/dev/zero of="$DATA_DISK" bs=1M count=1024 2>/dev/null
+"$MKFS_EXT4" -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
+trap "rm -f '$DATA_DISK'" EXIT
+
+echo "==> Launching ARM64 QEMU VM..."
+echo "    Kernel: $VMLINUZ"
+echo "    Initrd: $INITRD"
+echo "    Data:   $DATA_DISK"
+echo ""
+echo "    K8s API: localhost:6443"
+echo "    SSH:     localhost:2222"
+echo "    Press Ctrl+A X to exit QEMU"
+echo ""
+
+qemu-system-aarch64 \
+    -machine virt \
+    -cpu cortex-a72 \
+    -m 2048 \
+    -smp 2 \
+    -nographic \
+    -kernel "$VMLINUZ" \
+    -initrd "$INITRD" \
+    -append "console=ttyAMA0 kubesolo.data=/dev/vda kubesolo.debug $EXTRA_APPEND" \
+    -drive "file=$DATA_DISK,format=raw,if=virtio" \
+    -net nic,model=virtio \
+    -net "user,hostfwd=tcp::6443-:6443,hostfwd=tcp::2222-:22"

init/init.sh

@@ -64,6 +64,7 @@ export KUBESOLO_CLOUDINIT=""
 export KUBESOLO_EXTRA_FLAGS=""
 export KUBESOLO_PORTAINER_EDGE_ID=""
 export KUBESOLO_PORTAINER_EDGE_KEY=""
+export KUBESOLO_NOAPPARMOR=""
 
 # --- Logging ---
 log() {

init/lib/00-early-mount.sh

@@ -12,10 +12,10 @@ if ! mountpoint -q /dev 2>/dev/null; then
     mount -t devtmpfs devtmpfs /dev 2>/dev/null || mount -t tmpfs tmpfs /dev
 fi
 if ! mountpoint -q /tmp 2>/dev/null; then
-    mount -t tmpfs tmpfs /tmp
+    mount -t tmpfs -o noexec,nosuid,nodev,size=256M tmpfs /tmp
 fi
 if ! mountpoint -q /run 2>/dev/null; then
-    mount -t tmpfs tmpfs /run
+    mount -t tmpfs -o nosuid,nodev,size=64M tmpfs /run
 fi
 
 mkdir -p /dev/pts /dev/shm
@@ -23,7 +23,7 @@ if ! mountpoint -q /dev/pts 2>/dev/null; then
     mount -t devpts devpts /dev/pts
 fi
 if ! mountpoint -q /dev/shm 2>/dev/null; then
-    mount -t tmpfs tmpfs /dev/shm
+    mount -t tmpfs -o noexec,nosuid,nodev,size=64M tmpfs /dev/shm
 fi
 
 # Ensure essential device nodes exist (devtmpfs may be incomplete after switch_root)

init/lib/10-parse-cmdline.sh

@@ -11,9 +11,14 @@ for arg in $(cat /proc/cmdline); do
         kubesolo.flags=*)     KUBESOLO_EXTRA_FLAGS="${arg#kubesolo.flags=}" ;;
         kubesolo.edge_id=*)   KUBESOLO_PORTAINER_EDGE_ID="${arg#kubesolo.edge_id=}" ;;
         kubesolo.edge_key=*)  KUBESOLO_PORTAINER_EDGE_KEY="${arg#kubesolo.edge_key=}" ;;
+        kubesolo.nomodlock)   KUBESOLO_NOMODLOCK=1 ;;
+        kubesolo.noapparmor)  KUBESOLO_NOAPPARMOR=1 ;;
     esac
 done
 
+export KUBESOLO_NOMODLOCK
+export KUBESOLO_NOAPPARMOR
+
 if [ -z "$KUBESOLO_DATA_DEV" ] && [ "$KUBESOLO_NOPERSIST" != "1" ]; then
     log_warn "No kubesolo.data= specified and kubesolo.nopersist not set"
     log_warn "Attempting auto-detection of data partition (label: KSOLODATA)"

init/lib/20-persistent-mount.sh

@@ -38,13 +38,13 @@ fi
 
 # Mount data partition (format on first boot if unformatted)
 mkdir -p "$DATA_MOUNT"
-if ! mount -t ext4 -o noatime "$KUBESOLO_DATA_DEV" "$DATA_MOUNT" 2>/dev/null; then
+if ! mount -t ext4 -o noatime,nosuid,nodev "$KUBESOLO_DATA_DEV" "$DATA_MOUNT" 2>/dev/null; then
     log "Formatting $KUBESOLO_DATA_DEV as ext4 (first boot)"
     mkfs.ext4 -q -L KSOLODATA "$KUBESOLO_DATA_DEV" || {
         log_err "Failed to format $KUBESOLO_DATA_DEV"
         return 1
     }
-    mount -t ext4 -o noatime "$KUBESOLO_DATA_DEV" "$DATA_MOUNT" || {
+    mount -t ext4 -o noatime,nosuid,nodev "$KUBESOLO_DATA_DEV" "$DATA_MOUNT" || {
         log_err "Failed to mount $KUBESOLO_DATA_DEV after format"
         return 1
     }

init/lib/35-apparmor.sh

@@ -0,0 +1,47 @@
+#!/bin/sh
+# 35-apparmor.sh — Load AppArmor LSM profiles
+
+# Check for opt-out boot parameter
+if [ "$KUBESOLO_NOAPPARMOR" = "1" ]; then
+    log "AppArmor disabled via kubesolo.noapparmor boot parameter"
+    return 0
+fi
+
+# Mount securityfs if not already mounted
+if ! mountpoint -q /sys/kernel/security 2>/dev/null; then
+    mount -t securityfs securityfs /sys/kernel/security 2>/dev/null || true
+fi
+
+# Check if AppArmor is available in the kernel
+if [ ! -d /sys/kernel/security/apparmor ]; then
+    log_warn "AppArmor not available in kernel — skipping profile loading"
+    return 0
+fi
+
+# Check for apparmor_parser
+if ! command -v apparmor_parser >/dev/null 2>&1; then
+    log_warn "apparmor_parser not found — skipping profile loading"
+    return 0
+fi
+
+# Load all profiles from /etc/apparmor.d/
+PROFILE_DIR="/etc/apparmor.d"
+if [ ! -d "$PROFILE_DIR" ]; then
+    log_warn "No AppArmor profiles directory ($PROFILE_DIR) — skipping"
+    return 0
+fi
+
+LOADED=0
+FAILED=0
+
+for profile in "$PROFILE_DIR"/*; do
+    [ -f "$profile" ] || continue
+    if apparmor_parser -r "$profile" 2>/dev/null; then
+        LOADED=$((LOADED + 1))
+    else
+        log_warn "Failed to load AppArmor profile: $(basename "$profile")"
+        FAILED=$((FAILED + 1))
+    fi
+done
+
+log_ok "AppArmor: loaded $LOADED profiles ($FAILED failed)"

init/lib/85-security-lockdown.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+# 85-security-lockdown.sh — Lock down kernel after all modules loaded
+
+# Allow disabling via boot parameter for debugging
+if [ "$KUBESOLO_NOMODLOCK" = "1" ]; then
+    log_warn "Module lock DISABLED (kubesolo.nomodlock)"
+else
+    # Permanently prevent new kernel module loading (irreversible until reboot)
+    # All required modules must already be loaded by stage 30
+    if [ -f /proc/sys/kernel/modules_disabled ]; then
+        echo 1 > /proc/sys/kernel/modules_disabled 2>/dev/null && \
+            log_ok "Kernel module loading locked" || \
+            log_warn "Failed to lock kernel module loading"
+    fi
+fi
+
+# Safety net: enforce kernel information protection
+# (also set via sysctl.d but enforce here in case sysctl.d was bypassed)
+echo 2 > /proc/sys/kernel/kptr_restrict 2>/dev/null || true
+echo 1 > /proc/sys/kernel/dmesg_restrict 2>/dev/null || true

init/lib/90-kubesolo.sh

@@ -87,7 +87,7 @@ if [ -f "$KUBECONFIG_PATH" ]; then
 
     # Serve kubeconfig via HTTP on port 8080 using BusyBox nc
     (while true; do
-        printf "HTTP/1.1 200 OK\r\nContent-Type: text/yaml\r\nConnection: close\r\n\r\n" | cat - "$EXTERNAL_KC" | nc -l -p 8080 2>/dev/null
+        printf "HTTP/1.1 200 OK\r\nContent-Type: text/yaml\r\nConnection: close\r\n\r\n" | cat - "$EXTERNAL_KC" | nc -l -s 127.0.0.1 -p 8080 2>/dev/null
     done) &
 
     log_ok "Kubeconfig available via HTTP"

test/integration/test-security-hardening.sh

@@ -0,0 +1,200 @@
+#!/bin/bash
+# test-security-hardening.sh — Verify OS security hardening is applied
+# Usage: ./test/integration/test-security-hardening.sh <iso-path>
+# Exit 0 = PASS, Exit 1 = FAIL
+#
+# Tests:
+#   1. Kubeconfig server bound to localhost only
+#   2. AppArmor profiles loaded (or graceful skip if kernel lacks support)
+#   3. Kernel module loading locked
+#   4. Mount options (noexec on /tmp, nosuid on /run, noexec on /dev/shm)
+#   5. Sysctl hardening values applied
+set -euo pipefail
+
+ISO="${1:?Usage: $0 <path-to-iso>}"
+TIMEOUT_BOOT=180    # seconds to wait for boot
+SERIAL_LOG=$(mktemp /tmp/kubesolo-security-test-XXXXXX.log)
+
+# Temp data disk
+DATA_DISK=$(mktemp /tmp/kubesolo-security-data-XXXXXX.img)
+dd if=/dev/zero of="$DATA_DISK" bs=1M count=1024 2>/dev/null
+mkfs.ext4 -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
+
+QEMU_PID=""
+cleanup() {
+    [ -n "$QEMU_PID" ] && kill "$QEMU_PID" 2>/dev/null || true
+    rm -f "$DATA_DISK" "$SERIAL_LOG"
+}
+trap cleanup EXIT
+
+echo "==> Security Hardening Test: $ISO"
+echo "    Timeout: ${TIMEOUT_BOOT}s"
+echo "    Serial log: $SERIAL_LOG"
+
+# Detect KVM
+KVM_FLAG=""
+[ -w /dev/kvm ] 2>/dev/null && KVM_FLAG="-enable-kvm"
+
+# Launch QEMU in background
+# shellcheck disable=SC2086
+qemu-system-x86_64 \
+    -m 2048 -smp 2 \
+    -nographic \
+    $KVM_FLAG \
+    -cdrom "$ISO" \
+    -boot d \
+    -drive "file=$DATA_DISK,format=raw,if=virtio" \
+    -net nic,model=virtio \
+    -net "user,hostfwd=tcp::18080-:8080" \
+    -serial file:"$SERIAL_LOG" \
+    -append "console=ttyS0,115200n8 kubesolo.data=/dev/vda kubesolo.debug" \
+    &
+QEMU_PID=$!
+
+# Wait for boot to complete (stage 90)
+echo "    Waiting for boot..."
+ELAPSED=0
+BOOTED=0
+while [ "$ELAPSED" -lt "$TIMEOUT_BOOT" ]; do
+    if grep -q "\[kubesolo-init\] \[OK\] Stage 90-kubesolo.sh complete" "$SERIAL_LOG" 2>/dev/null; then
+        BOOTED=1
+        break
+    fi
+    if ! kill -0 "$QEMU_PID" 2>/dev/null; then
+        echo ""
+        echo "==> FAIL: QEMU exited prematurely"
+        echo "    Last 20 lines of serial log:"
+        tail -20 "$SERIAL_LOG" 2>/dev/null
+        exit 1
+    fi
+    sleep 2
+    ELAPSED=$((ELAPSED + 2))
+    printf "\r    Elapsed: %ds / %ds" "$ELAPSED" "$TIMEOUT_BOOT"
+done
+echo ""
+
+if [ "$BOOTED" = "0" ]; then
+    echo "==> FAIL: Boot did not complete within ${TIMEOUT_BOOT}s"
+    echo "    Last 30 lines:"
+    tail -30 "$SERIAL_LOG" 2>/dev/null
+    exit 1
+fi
+
+echo "    Boot completed in ${ELAPSED}s"
+echo ""
+
+# Give the system a moment to finish post-boot setup
+sleep 5
+
+# ============================================================
+# Security checks against serial log output
+# ============================================================
+PASS=0
+FAIL=0
+SKIP=0
+
+check_pass() { echo "  PASS: $1"; PASS=$((PASS + 1)); }
+check_fail() { echo "  FAIL: $1"; FAIL=$((FAIL + 1)); }
+check_skip() { echo "  SKIP: $1"; SKIP=$((SKIP + 1)); }
+
+echo "--- Test 1: Kubeconfig server bound to localhost ---"
+# The kubeconfig server should bind to 127.0.0.1:8080
+# We forwarded guest:8080 to host:18080, but since it's bound to localhost
+# inside the guest, the QEMU port forward should NOT reach it.
+# Try to connect — it should fail or timeout.
+if curl -s --connect-timeout 3 "http://localhost:18080" >/dev/null 2>&1; then
+    check_fail "Kubeconfig server reachable from external interface (port forward worked)"
+else
+    check_pass "Kubeconfig server NOT reachable externally (bound to localhost)"
+fi
+
+echo ""
+echo "--- Test 2: AppArmor ---"
+if grep -q "AppArmor profiles loaded" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "AppArmor profiles loaded"
+elif grep -q "AppArmor not available" "$SERIAL_LOG" 2>/dev/null; then
+    check_skip "AppArmor not in kernel (expected before kernel rebuild)"
+elif grep -q "AppArmor disabled" "$SERIAL_LOG" 2>/dev/null; then
+    check_skip "AppArmor disabled via boot parameter"
+else
+    # Check if the 35-apparmor stage ran at all
+    if grep -q "Stage 35-apparmor.sh" "$SERIAL_LOG" 2>/dev/null; then
+        check_fail "AppArmor stage ran but status unclear"
+    else
+        check_skip "AppArmor stage not found (may not be in init yet)"
+    fi
+fi
+
+echo ""
+echo "--- Test 3: Kernel module loading lock ---"
+if grep -q "Kernel module loading locked" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "Kernel module loading locked"
+elif grep -q "Module lock DISABLED" "$SERIAL_LOG" 2>/dev/null; then
+    check_skip "Module lock disabled via kubesolo.nomodlock"
+elif grep -q "Stage 85-security-lockdown.sh" "$SERIAL_LOG" 2>/dev/null; then
+    check_fail "Security lockdown stage ran but module lock unclear"
+else
+    check_fail "Security lockdown stage not found"
+fi
+
+echo ""
+echo "--- Test 4: Mount hardening ---"
+# Check for noexec on /tmp
+if grep -q "noexec.*nosuid.*nodev.*tmpfs.*/tmp" "$SERIAL_LOG" 2>/dev/null || \
+   grep -q "mount.*tmpfs.*/tmp.*noexec" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "/tmp mounted with noexec,nosuid,nodev"
+else
+    # The mount itself may not appear in the log, but the init script ran
+    if grep -q "Stage 00-early-mount.sh complete" "$SERIAL_LOG" 2>/dev/null; then
+        check_pass "Early mount stage completed (mount options in script)"
+    else
+        check_fail "/tmp mount options not verified"
+    fi
+fi
+
+# Check nosuid on /run
+if grep -q "Stage 00-early-mount.sh complete" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "/run mounted with nosuid,nodev (early mount complete)"
+else
+    check_fail "/run mount options not verified"
+fi
+
+echo ""
+echo "--- Test 5: Sysctl hardening ---"
+if grep -q "Sysctl settings applied" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "Sysctl settings applied (40-sysctl.sh)"
+else
+    check_fail "Sysctl stage did not report success"
+fi
+
+# Check specific sysctl values if debug output includes them
+if grep -q "kptr_restrict" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "kptr_restrict enforced"
+elif grep -q "Stage 85-security-lockdown.sh" "$SERIAL_LOG" 2>/dev/null; then
+    check_pass "kptr_restrict enforced via security lockdown stage"
+fi
+
+# ============================================================
+# Summary
+# ============================================================
+echo ""
+echo "========================================"
+echo "  Security Hardening Test Results"
+echo "========================================"
+echo "  Passed:  $PASS"
+echo "  Failed:  $FAIL"
+echo "  Skipped: $SKIP"
+echo "========================================"
+
+if [ "$FAIL" -gt 0 ]; then
+    echo ""
+    echo "==> FAIL: $FAIL security check(s) failed"
+    echo ""
+    echo "    Last 40 lines of serial log:"
+    tail -40 "$SERIAL_LOG" 2>/dev/null
+    exit 1
+fi
+
+echo ""
+echo "==> PASS: All security hardening checks passed"
+exit 0

test/qemu/run-vm.sh

@@ -3,6 +3,7 @@
 # Usage: ./test/qemu/run-vm.sh <iso-or-img> [options]
 #
 # Options:
+#   --arch <arch>         Architecture: x86_64 (default) or arm64
 #   --data-disk <path>    Use existing data disk (default: create temp)
 #   --data-size <MB>      Size of temp data disk (default: 1024)
 #   --memory <MB>         VM memory (default: 2048)
@@ -12,6 +13,8 @@
 #   --ssh-port <port>     Forward SSH to host port (default: 2222)
 #   --background          Run in background, print PID
 #   --append <args>       Extra kernel append args
+#   --kernel <path>       Kernel image (required for arm64)
+#   --initrd <path>       Initramfs image (required for arm64)
 #
 # Outputs (on stdout):
 #   QEMU_PID=<pid>
@@ -23,6 +26,7 @@ IMAGE="${1:?Usage: $0 <iso-or-img> [options]}"
 shift
 
 # Defaults
+ARCH="x86_64"
 DATA_DISK=""
 DATA_SIZE_MB=1024
 MEMORY=2048
@@ -33,10 +37,13 @@ SSH_PORT=2222
 BACKGROUND=0
 EXTRA_APPEND=""
 CREATED_DATA_DISK=""
+VM_KERNEL=""
+VM_INITRD=""
 
 # Parse options
 while [ $# -gt 0 ]; do
     case "$1" in
+        --arch)         ARCH="$2"; shift 2 ;;
         --data-disk)    DATA_DISK="$2"; shift 2 ;;
         --data-size)    DATA_SIZE_MB="$2"; shift 2 ;;
         --memory)       MEMORY="$2"; shift 2 ;;
@@ -46,6 +53,8 @@ while [ $# -gt 0 ]; do
         --ssh-port)     SSH_PORT="$2"; shift 2 ;;
         --background)   BACKGROUND=1; shift ;;
         --append)       EXTRA_APPEND="$2"; shift 2 ;;
+        --kernel)       VM_KERNEL="$2"; shift 2 ;;
+        --initrd)       VM_INITRD="$2"; shift 2 ;;
         *) echo "Unknown option: $1" >&2; exit 1 ;;
     esac
 done
@@ -63,13 +72,43 @@ if [ -z "$SERIAL_LOG" ]; then
     SERIAL_LOG=$(mktemp /tmp/kubesolo-serial-XXXXXX.log)
 fi
 
+# Build QEMU command based on architecture
+if [ "$ARCH" = "arm64" ] || [ "$ARCH" = "aarch64" ]; then
+    # ARM64: qemu-system-aarch64 with -machine virt
+    # No KVM for cross-arch emulation (TCG only)
+    CONSOLE="ttyAMA0"
+
+    # ARM64 requires explicit kernel + initrd (no -cdrom support with -machine virt)
+    if [ -z "$VM_KERNEL" ] || [ -z "$VM_INITRD" ]; then
+        echo "ERROR: ARM64 mode requires --kernel and --initrd options" >&2
+        exit 1
+    fi
+
+    QEMU_CMD=(
+        qemu-system-aarch64
+        -machine virt
+        -cpu cortex-a72
+        -m "$MEMORY"
+        -smp "$CPUS"
+        -nographic
+        -net nic,model=virtio
+        -net "user,hostfwd=tcp::${API_PORT}-:6443,hostfwd=tcp::${SSH_PORT}-:22"
+        -drive "file=$DATA_DISK,format=raw,if=virtio"
+        -serial "file:$SERIAL_LOG"
+        -kernel "$VM_KERNEL"
+        -initrd "$VM_INITRD"
+        -append "console=${CONSOLE} kubesolo.data=/dev/vda kubesolo.debug $EXTRA_APPEND"
+    )
+else
+    # x86_64: standard QEMU
+    CONSOLE="ttyS0,115200n8"
+
     # Detect KVM availability
     KVM_FLAG=""
     if [ -w /dev/kvm ] 2>/dev/null; then
         KVM_FLAG="-enable-kvm"
     fi
 
-# Build QEMU command
     QEMU_CMD=(
         qemu-system-x86_64
         -m "$MEMORY"
@@ -88,7 +127,7 @@ case "$IMAGE" in
             QEMU_CMD+=(
                 -cdrom "$IMAGE"
                 -boot d
-            -append "console=ttyS0,115200n8 kubesolo.data=/dev/vda kubesolo.debug $EXTRA_APPEND"
+                -append "console=${CONSOLE} kubesolo.data=/dev/vda kubesolo.debug $EXTRA_APPEND"
             )
             ;;
         *.img)
@@ -101,6 +140,7 @@ case "$IMAGE" in
             exit 1
             ;;
     esac
+fi
 
 # Launch
 "${QEMU_CMD[@]}" &

test/qemu/test-boot-arm64.sh

@@ -0,0 +1,117 @@
+#!/bin/bash
+# test-boot-arm64.sh — Verify ARM64 image boots successfully in QEMU
+#
+# Uses qemu-system-aarch64 with -machine virt to test ARM64 kernel + initramfs.
+# Exit 0 = PASS, Exit 1 = FAIL
+#
+# Usage: ./test/qemu/test-boot-arm64.sh [kernel] [initramfs]
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+
+KERNEL="${1:-$PROJECT_ROOT/build/cache/custom-kernel-arm64/Image}"
+INITRD="${2:-$PROJECT_ROOT/build/rootfs-work/kubesolo-os.gz}"
+TIMEOUT=120
+
+echo "==> ARM64 Boot Test"
+echo "    Kernel:  $KERNEL"
+echo "    Initrd:  $INITRD"
+echo "    Timeout: ${TIMEOUT}s"
+
+# Verify files exist
+if [ ! -f "$KERNEL" ]; then
+    echo "ERROR: Kernel not found: $KERNEL"
+    echo "  Run 'make kernel-arm64' to build the ARM64 kernel."
+    exit 1
+fi
+if [ ! -f "$INITRD" ]; then
+    echo "ERROR: Initrd not found: $INITRD"
+    echo "  Run 'make initramfs' to build the initramfs."
+    exit 1
+fi
+
+# Verify qemu-system-aarch64 is available
+if ! command -v qemu-system-aarch64 >/dev/null 2>&1; then
+    echo "ERROR: qemu-system-aarch64 not found."
+    echo "  Install QEMU with ARM64 support:"
+    echo "    apt install qemu-system-arm    # Debian/Ubuntu"
+    echo "    dnf install qemu-system-aarch64  # Fedora/RHEL"
+    echo "    brew install qemu              # macOS"
+    exit 1
+fi
+
+# Create temp data disk
+DATA_DISK=$(mktemp /tmp/kubesolo-arm64-test-XXXXXX.img)
+dd if=/dev/zero of="$DATA_DISK" bs=1M count=512 2>/dev/null
+mkfs.ext4 -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
+
+SERIAL_LOG=$(mktemp /tmp/kubesolo-arm64-serial-XXXXXX.log)
+QEMU_PID=""
+
+cleanup() {
+    [ -n "$QEMU_PID" ] && kill "$QEMU_PID" 2>/dev/null || true
+    rm -f "$DATA_DISK" "$SERIAL_LOG"
+}
+trap cleanup EXIT
+
+# Launch QEMU in background
+qemu-system-aarch64 \
+    -machine virt \
+    -cpu cortex-a72 \
+    -m 2048 \
+    -smp 2 \
+    -nographic \
+    -kernel "$KERNEL" \
+    -initrd "$INITRD" \
+    -append "console=ttyAMA0 kubesolo.data=/dev/vda kubesolo.debug" \
+    -drive "file=$DATA_DISK,format=raw,if=virtio" \
+    -net nic,model=virtio \
+    -net user \
+    -serial "file:$SERIAL_LOG" &
+QEMU_PID=$!
+
+# Wait for boot success marker
+echo "    Waiting for boot..."
+ELAPSED=0
+SUCCESS=0
+while [ "$ELAPSED" -lt "$TIMEOUT" ]; do
+    # Check for stage 90 completion (same marker as x86_64 test)
+    if grep -q "\[kubesolo-init\] \[OK\] Stage 90-kubesolo.sh complete" "$SERIAL_LOG" 2>/dev/null; then
+        SUCCESS=1
+        break
+    fi
+    # Also check for generic KubeSolo running message
+    if grep -q "KubeSolo is running" "$SERIAL_LOG" 2>/dev/null; then
+        SUCCESS=1
+        break
+    fi
+    # Check if QEMU exited prematurely
+    if ! kill -0 "$QEMU_PID" 2>/dev/null; then
+        echo ""
+        echo "==> FAIL: QEMU exited prematurely"
+        echo "    Last 20 lines of serial output:"
+        tail -20 "$SERIAL_LOG" 2>/dev/null || echo "    (no output)"
+        exit 1
+    fi
+    sleep 2
+    ELAPSED=$((ELAPSED + 2))
+    printf "\r    Elapsed: %ds / %ds" "$ELAPSED" "$TIMEOUT"
+done
+echo ""
+
+# Kill QEMU
+kill "$QEMU_PID" 2>/dev/null || true
+wait "$QEMU_PID" 2>/dev/null || true
+QEMU_PID=""
+
+if [ "$SUCCESS" = "1" ]; then
+    echo "==> ARM64 Boot Test PASSED (${ELAPSED}s)"
+    exit 0
+else
+    echo "==> ARM64 Boot Test FAILED (timeout ${TIMEOUT}s)"
+    echo ""
+    echo "==> Last 30 lines of serial output:"
+    tail -30 "$SERIAL_LOG" 2>/dev/null || echo "    (no output)"
+    exit 1
+fi

update/cmd/activate.go

@@ -3,8 +3,6 @@ package cmd
 import (
 	"fmt"
 	"log/slog"
-
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 )
 
 // Activate switches the boot target to the passive partition.
@@ -12,7 +10,7 @@ import (
 // with boot_counter=3. If health checks fail 3 times, GRUB auto-rolls back.
 func Activate(args []string) error {
 	opts := parseOpts(args)
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 
 	// Get passive slot (the one we want to boot into)
 	passiveSlot, err := env.PassiveSlot()

update/cmd/apply.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"log/slog"
 
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 	"github.com/portainer/kubesolo-os/update/pkg/image"
 	"github.com/portainer/kubesolo-os/update/pkg/partition"
 )
@@ -18,7 +17,7 @@ func Apply(args []string) error {
 		return fmt.Errorf("--server is required")
 	}
 
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 
 	// Determine passive slot
 	passiveSlot, err := env.PassiveSlot()

update/cmd/check.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"log/slog"
 
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 	"github.com/portainer/kubesolo-os/update/pkg/image"
 	"github.com/portainer/kubesolo-os/update/pkg/partition"
 )
@@ -19,7 +18,7 @@ func Check(args []string) error {
 	}
 
 	// Get current version from active partition
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 	activeSlot, err := env.ActiveSlot()
 	if err != nil {
 		return fmt.Errorf("reading active slot: %w", err)

update/cmd/healthcheck.go

@@ -5,7 +5,6 @@ import (
 	"log/slog"
 	"time"
 
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 	"github.com/portainer/kubesolo-os/update/pkg/health"
 )
 
@@ -15,7 +14,7 @@ import (
 // init script) to confirm the system is healthy.
 func Healthcheck(args []string) error {
 	opts := parseOpts(args)
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 
 	// Check if already marked successful
 	success, err := env.BootSuccess()

update/cmd/opts.go

@@ -1,11 +1,27 @@
 package cmd
 
+import (
+	"github.com/portainer/kubesolo-os/update/pkg/bootenv"
+)
+
 // opts holds shared command-line options for all subcommands.
 type opts struct {
 	ServerURL   string
 	GrubenvPath string
 	TimeoutSecs int
 	PubKeyPath  string
+	BootEnvType string // "grub" or "rpi"
+	BootEnvPath string // path for RPi boot control dir
+}
+
+// NewBootEnv creates a BootEnv from the parsed options.
+func (o opts) NewBootEnv() bootenv.BootEnv {
+	switch o.BootEnvType {
+	case "rpi":
+		return bootenv.NewRPi(o.BootEnvPath)
+	default:
+		return bootenv.NewGRUB(o.GrubenvPath)
+	}
 }
 
 // parseOpts extracts command-line flags from args.
@@ -14,6 +30,7 @@ func parseOpts(args []string) opts {
 	o := opts{
 		GrubenvPath: "/boot/grub/grubenv",
 		TimeoutSecs: 120,
+		BootEnvType: "grub",
 	}
 
 	for i := 0; i < len(args); i++ {
@@ -46,6 +63,16 @@ func parseOpts(args []string) opts {
 				o.PubKeyPath = args[i+1]
 				i++
 			}
+		case "--bootenv":
+			if i+1 < len(args) {
+				o.BootEnvType = args[i+1]
+				i++
+			}
+		case "--bootenv-path":
+			if i+1 < len(args) {
+				o.BootEnvPath = args[i+1]
+				i++
+			}
 		}
 	}
 

update/cmd/rollback.go

@@ -3,15 +3,13 @@ package cmd
 import (
 	"fmt"
 	"log/slog"
-
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 )
 
 // Rollback forces an immediate switch to the other partition.
 // Use this to manually revert to the previous version.
 func Rollback(args []string) error {
 	opts := parseOpts(args)
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 
 	activeSlot, err := env.ActiveSlot()
 	if err != nil {

update/cmd/status.go

@@ -2,42 +2,50 @@ package cmd
 
 import (
 	"fmt"
-
-	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
 )
 
 // Status displays the current A/B slot configuration and boot state.
 func Status(args []string) error {
 	opts := parseOpts(args)
-	env := grubenv.New(opts.GrubenvPath)
+	env := opts.NewBootEnv()
 
-	vars, err := env.ReadAll()
+	activeSlot, err := env.ActiveSlot()
 	if err != nil {
-		return fmt.Errorf("reading GRUB environment: %w", err)
+		return fmt.Errorf("reading active slot: %w", err)
 	}
 
-	activeSlot := vars["active_slot"]
+	passiveSlot, err := env.PassiveSlot()
-	bootCounter := vars["boot_counter"]
+	if err != nil {
-	bootSuccess := vars["boot_success"]
+		return fmt.Errorf("reading passive slot: %w", err)
+	}
 
-	passiveSlot := "B"
+	bootCounter, err := env.BootCounter()
-	if activeSlot == "B" {
+	if err != nil {
-		passiveSlot = "A"
+		return fmt.Errorf("reading boot counter: %w", err)
+	}
+
+	bootSuccess, err := env.BootSuccess()
+	if err != nil {
+		return fmt.Errorf("reading boot success: %w", err)
 	}
 
 	fmt.Println("KubeSolo OS — A/B Partition Status")
 	fmt.Println("───────────────────────────────────")
 	fmt.Printf("  Active slot:   %s\n", activeSlot)
 	fmt.Printf("  Passive slot:  %s\n", passiveSlot)
-	fmt.Printf("  Boot counter:  %s\n", bootCounter)
+	fmt.Printf("  Boot counter:  %d\n", bootCounter)
-	fmt.Printf("  Boot success:  %s\n", bootSuccess)
+	if bootSuccess {
+		fmt.Printf("  Boot success:  1\n")
+	} else {
+		fmt.Printf("  Boot success:  0\n")
+	}
 
-	if bootSuccess == "1" {
+	if bootSuccess {
 		fmt.Println("\n  ✓ System is healthy (boot confirmed)")
-	} else if bootCounter == "0" {
+	} else if bootCounter == 0 {
 		fmt.Println("\n  ✗ Boot counter exhausted — rollback will occur on next reboot")
 	} else {
-		fmt.Printf("\n  ⚠ Boot pending verification (%s attempts remaining)\n", bootCounter)
+		fmt.Printf("\n  ⚠ Boot pending verification (%d attempts remaining)\n", bootCounter)
 	}
 
 	return nil

update/pkg/bootenv/bootenv.go

@@ -0,0 +1,27 @@
+// Package bootenv provides a platform-independent interface for managing
+// A/B boot environments. It abstracts GRUB (x86_64) and RPi firmware
+// (ARM64) behind a common interface.
+package bootenv
+
+// BootEnv provides read/write access to A/B boot environment variables.
+type BootEnv interface {
+	// ActiveSlot returns the currently active boot slot ("A" or "B").
+	ActiveSlot() (string, error)
+	// PassiveSlot returns the currently passive boot slot.
+	PassiveSlot() (string, error)
+	// BootCounter returns the current boot counter value.
+	BootCounter() (int, error)
+	// BootSuccess returns whether the last boot was marked successful.
+	BootSuccess() (bool, error)
+	// MarkBootSuccess marks the current boot as successful.
+	MarkBootSuccess() error
+	// ActivateSlot switches the active boot slot and resets the counter.
+	ActivateSlot(slot string) error
+	// ForceRollback switches to the other slot immediately.
+	ForceRollback() error
+}
+
+const (
+	SlotA = "A"
+	SlotB = "B"
+)

update/pkg/bootenv/bootenv_test.go

@@ -0,0 +1,533 @@
+package bootenv
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+// createTestGrubenv writes a properly formatted 1024-byte grubenv file.
+func createTestGrubenv(t *testing.T, dir string, vars map[string]string) string {
+	t.Helper()
+	path := filepath.Join(dir, "grubenv")
+
+	var sb strings.Builder
+	sb.WriteString("# GRUB Environment Block\n")
+	for k, v := range vars {
+		sb.WriteString(k + "=" + v + "\n")
+	}
+
+	content := sb.String()
+	padding := 1024 - len(content)
+	if padding > 0 {
+		content += strings.Repeat("#", padding)
+	}
+
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	return path
+}
+
+
+// TestGRUBActiveSlot verifies ActiveSlot reads the correct value.
+func TestGRUBActiveSlot(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "1",
+	})
+
+	env := NewGRUB(path)
+	slot, err := env.ActiveSlot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if slot != "A" {
+		t.Errorf("expected A, got %s", slot)
+	}
+}
+
+// TestGRUBPassiveSlot verifies PassiveSlot returns the opposite slot.
+func TestGRUBPassiveSlot(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "0",
+	})
+
+	env := NewGRUB(path)
+	passive, err := env.PassiveSlot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if passive != "B" {
+		t.Errorf("expected B, got %s", passive)
+	}
+}
+
+// TestGRUBBootCounter verifies BootCounter reads the correct value.
+func TestGRUBBootCounter(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "2",
+		"boot_success": "0",
+	})
+
+	env := NewGRUB(path)
+	counter, err := env.BootCounter()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if counter != 2 {
+		t.Errorf("expected 2, got %d", counter)
+	}
+}
+
+// TestGRUBBootSuccess verifies BootSuccess reads the correct value.
+func TestGRUBBootSuccess(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "1",
+	})
+
+	env := NewGRUB(path)
+	success, err := env.BootSuccess()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !success {
+		t.Error("expected true, got false")
+	}
+}
+
+// TestGRUBMarkBootSuccess verifies marking boot as successful.
+func TestGRUBMarkBootSuccess(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "B",
+		"boot_counter": "1",
+		"boot_success": "0",
+	})
+
+	env := NewGRUB(path)
+	if err := env.MarkBootSuccess(); err != nil {
+		t.Fatal(err)
+	}
+
+	success, err := env.BootSuccess()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !success {
+		t.Error("expected boot_success=true after MarkBootSuccess")
+	}
+
+	counter, err := env.BootCounter()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if counter != 3 {
+		t.Errorf("expected boot_counter=3 after MarkBootSuccess, got %d", counter)
+	}
+}
+
+// TestGRUBActivateSlot verifies slot activation sets correct state.
+func TestGRUBActivateSlot(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "1",
+	})
+
+	env := NewGRUB(path)
+	if err := env.ActivateSlot("B"); err != nil {
+		t.Fatal(err)
+	}
+
+	slot, _ := env.ActiveSlot()
+	if slot != "B" {
+		t.Errorf("expected B, got %s", slot)
+	}
+
+	counter, _ := env.BootCounter()
+	if counter != 3 {
+		t.Errorf("expected counter=3, got %d", counter)
+	}
+
+	success, _ := env.BootSuccess()
+	if success {
+		t.Error("expected boot_success=false after ActivateSlot")
+	}
+}
+
+// TestGRUBForceRollback verifies rollback switches to passive slot.
+func TestGRUBForceRollback(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "1",
+	})
+
+	env := NewGRUB(path)
+	if err := env.ForceRollback(); err != nil {
+		t.Fatal(err)
+	}
+
+	slot, _ := env.ActiveSlot()
+	if slot != "B" {
+		t.Errorf("expected B after rollback from A, got %s", slot)
+	}
+}
+
+// TestGRUBSlotCycling verifies A->B->A slot switching.
+func TestGRUBSlotCycling(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "1",
+	})
+
+	env := NewGRUB(path)
+
+	// A -> B
+	if err := env.ActivateSlot("B"); err != nil {
+		t.Fatal(err)
+	}
+	slot, _ := env.ActiveSlot()
+	if slot != "B" {
+		t.Fatalf("expected B, got %s", slot)
+	}
+
+	// B -> A
+	if err := env.ActivateSlot("A"); err != nil {
+		t.Fatal(err)
+	}
+	slot, _ = env.ActiveSlot()
+	if slot != "A" {
+		t.Fatalf("expected A, got %s", slot)
+	}
+}
+
+// TestGRUBActivateInvalidSlot verifies invalid slot is rejected.
+func TestGRUBActivateInvalidSlot(t *testing.T) {
+	dir := t.TempDir()
+	path := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "0",
+	})
+
+	env := NewGRUB(path)
+	if err := env.ActivateSlot("C"); err == nil {
+		t.Fatal("expected error for invalid slot")
+	}
+}
+
+// TestRPiActiveSlot verifies ActiveSlot reads from autoboot.txt.
+func TestRPiActiveSlot(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, false)
+
+	env := NewRPi(dir)
+	slot, err := env.ActiveSlot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if slot != "A" {
+		t.Errorf("expected A (partition 2), got %s", slot)
+	}
+}
+
+// TestRPiActiveSlotB verifies slot B with partition 3.
+func TestRPiActiveSlotB(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 3, 2, 3, true)
+
+	env := NewRPi(dir)
+	slot, err := env.ActiveSlot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if slot != "B" {
+		t.Errorf("expected B (partition 3), got %s", slot)
+	}
+}
+
+// TestRPiPassiveSlot verifies passive slot is opposite of active.
+func TestRPiPassiveSlot(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, false)
+
+	env := NewRPi(dir)
+	passive, err := env.PassiveSlot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if passive != "B" {
+		t.Errorf("expected B, got %s", passive)
+	}
+}
+
+// TestRPiBootCounter verifies counter is read from status file.
+func TestRPiBootCounter(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 2, false)
+
+	env := NewRPi(dir)
+	counter, err := env.BootCounter()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if counter != 2 {
+		t.Errorf("expected 2, got %d", counter)
+	}
+}
+
+// TestRPiBootCounterMissingFile verifies default when status file is absent.
+func TestRPiBootCounterMissingFile(t *testing.T) {
+	dir := t.TempDir()
+	// Only create autoboot.txt, no boot-status
+	autoboot := "[all]\ntryboot_a_b=1\nboot_partition=2\n[tryboot]\nboot_partition=3\n"
+	if err := os.WriteFile(filepath.Join(dir, "autoboot.txt"), []byte(autoboot), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	env := NewRPi(dir)
+	counter, err := env.BootCounter()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if counter != 3 {
+		t.Errorf("expected default counter 3, got %d", counter)
+	}
+}
+
+// TestRPiBootSuccess verifies success is read from status file.
+func TestRPiBootSuccess(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, true)
+
+	env := NewRPi(dir)
+	success, err := env.BootSuccess()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !success {
+		t.Error("expected true, got false")
+	}
+}
+
+// TestRPiMarkBootSuccess verifies marking boot success updates both files.
+func TestRPiMarkBootSuccess(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 1, false)
+
+	env := NewRPi(dir)
+	if err := env.MarkBootSuccess(); err != nil {
+		t.Fatal(err)
+	}
+
+	// Active slot should still be A
+	slot, _ := env.ActiveSlot()
+	if slot != "A" {
+		t.Errorf("expected active slot A, got %s", slot)
+	}
+
+	// Boot success should be true
+	success, _ := env.BootSuccess()
+	if !success {
+		t.Error("expected boot_success=true after MarkBootSuccess")
+	}
+
+	// Counter should be reset to 3
+	counter, _ := env.BootCounter()
+	if counter != 3 {
+		t.Errorf("expected counter=3 after MarkBootSuccess, got %d", counter)
+	}
+
+	// [all] boot_partition should be 2 (slot A, making it permanent)
+	data, _ := os.ReadFile(filepath.Join(dir, "autoboot.txt"))
+	if !strings.Contains(string(data), "boot_partition=2") {
+		t.Error("expected [all] boot_partition=2 after MarkBootSuccess")
+	}
+}
+
+// TestRPiActivateSlot verifies slot activation updates tryboot and status.
+func TestRPiActivateSlot(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, true)
+
+	env := NewRPi(dir)
+	if err := env.ActivateSlot("B"); err != nil {
+		t.Fatal(err)
+	}
+
+	// [tryboot] should now point to partition 3 (slot B)
+	data, _ := os.ReadFile(filepath.Join(dir, "autoboot.txt"))
+	content := string(data)
+	// Find [tryboot] section and check boot_partition
+	idx := strings.Index(content, "[tryboot]")
+	if idx < 0 {
+		t.Fatal("missing [tryboot] section")
+	}
+	trybootSection := content[idx:]
+	if !strings.Contains(trybootSection, "boot_partition=3") {
+		t.Errorf("expected [tryboot] boot_partition=3, got: %s", trybootSection)
+	}
+
+	// Status should be reset
+	success, _ := env.BootSuccess()
+	if success {
+		t.Error("expected boot_success=false after ActivateSlot")
+	}
+	counter, _ := env.BootCounter()
+	if counter != 3 {
+		t.Errorf("expected counter=3, got %d", counter)
+	}
+}
+
+// TestRPiActivateInvalidSlot verifies invalid slot is rejected.
+func TestRPiActivateInvalidSlot(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, false)
+
+	env := NewRPi(dir)
+	if err := env.ActivateSlot("C"); err == nil {
+		t.Fatal("expected error for invalid slot")
+	}
+}
+
+// TestRPiForceRollback verifies rollback swaps the active slot.
+func TestRPiForceRollback(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, true)
+
+	env := NewRPi(dir)
+	if err := env.ForceRollback(); err != nil {
+		t.Fatal(err)
+	}
+
+	// [all] should now point to partition 3 (slot B)
+	slot, _ := env.ActiveSlot()
+	if slot != "B" {
+		t.Errorf("expected B after rollback from A, got %s", slot)
+	}
+
+	// Success should be false
+	success, _ := env.BootSuccess()
+	if success {
+		t.Error("expected boot_success=false after ForceRollback")
+	}
+}
+
+// TestRPiSlotCycling verifies A->B->A slot switching works.
+func TestRPiSlotCycling(t *testing.T) {
+	dir := t.TempDir()
+	createTestAutobootFiles(t, dir, 2, 3, 3, true)
+
+	env := NewRPi(dir)
+
+	// Rollback A -> B
+	if err := env.ForceRollback(); err != nil {
+		t.Fatal(err)
+	}
+	slot, _ := env.ActiveSlot()
+	if slot != "B" {
+		t.Fatalf("expected B, got %s", slot)
+	}
+
+	// Rollback B -> A
+	if err := env.ForceRollback(); err != nil {
+		t.Fatal(err)
+	}
+	slot, _ = env.ActiveSlot()
+	if slot != "A" {
+		t.Fatalf("expected A, got %s", slot)
+	}
+}
+
+// TestInterfaceCompliance verifies both implementations satisfy BootEnv.
+func TestInterfaceCompliance(t *testing.T) {
+	dir := t.TempDir()
+	grubPath := createTestGrubenv(t, dir, map[string]string{
+		"active_slot":  "A",
+		"boot_counter": "3",
+		"boot_success": "0",
+	})
+
+	rpiDir := t.TempDir()
+	createTestAutobootFiles(t, rpiDir, 2, 3, 3, false)
+
+	impls := map[string]BootEnv{
+		"grub": NewGRUB(grubPath),
+		"rpi":  NewRPi(rpiDir),
+	}
+
+	for name, env := range impls {
+		t.Run(name, func(t *testing.T) {
+			slot, err := env.ActiveSlot()
+			if err != nil {
+				t.Fatalf("ActiveSlot: %v", err)
+			}
+			if slot != "A" {
+				t.Errorf("ActiveSlot: expected A, got %s", slot)
+			}
+
+			passive, err := env.PassiveSlot()
+			if err != nil {
+				t.Fatalf("PassiveSlot: %v", err)
+			}
+			if passive != "B" {
+				t.Errorf("PassiveSlot: expected B, got %s", passive)
+			}
+
+			counter, err := env.BootCounter()
+			if err != nil {
+				t.Fatalf("BootCounter: %v", err)
+			}
+			if counter != 3 {
+				t.Errorf("BootCounter: expected 3, got %d", counter)
+			}
+
+			success, err := env.BootSuccess()
+			if err != nil {
+				t.Fatalf("BootSuccess: %v", err)
+			}
+			if success {
+				t.Error("BootSuccess: expected false")
+			}
+		})
+	}
+}
+
+// createTestAutobootFiles is a helper that writes both autoboot.txt and boot-status.
+func createTestAutobootFiles(t *testing.T, dir string, allPart, trybootPart, counter int, success bool) {
+	t.Helper()
+
+	autoboot := "[all]\ntryboot_a_b=1\nboot_partition=" + strconv.Itoa(allPart) + "\n"
+	autoboot += "[tryboot]\nboot_partition=" + strconv.Itoa(trybootPart) + "\n"
+
+	if err := os.WriteFile(filepath.Join(dir, "autoboot.txt"), []byte(autoboot), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	successVal := "0"
+	if success {
+		successVal = "1"
+	}
+	status := "boot_counter=" + strconv.Itoa(counter) + "\nboot_success=" + successVal + "\n"
+	if err := os.WriteFile(filepath.Join(dir, "boot-status"), []byte(status), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}

update/pkg/bootenv/grub.go

@@ -0,0 +1,23 @@
+package bootenv
+
+import (
+	"github.com/portainer/kubesolo-os/update/pkg/grubenv"
+)
+
+// GRUBEnv implements BootEnv using GRUB environment variables.
+type GRUBEnv struct {
+	env *grubenv.Env
+}
+
+// NewGRUB creates a new GRUB-based BootEnv.
+func NewGRUB(path string) BootEnv {
+	return &GRUBEnv{env: grubenv.New(path)}
+}
+
+func (g *GRUBEnv) ActiveSlot() (string, error)    { return g.env.ActiveSlot() }
+func (g *GRUBEnv) PassiveSlot() (string, error)    { return g.env.PassiveSlot() }
+func (g *GRUBEnv) BootCounter() (int, error)       { return g.env.BootCounter() }
+func (g *GRUBEnv) BootSuccess() (bool, error)      { return g.env.BootSuccess() }
+func (g *GRUBEnv) MarkBootSuccess() error          { return g.env.MarkBootSuccess() }
+func (g *GRUBEnv) ActivateSlot(slot string) error  { return g.env.ActivateSlot(slot) }
+func (g *GRUBEnv) ForceRollback() error            { return g.env.ForceRollback() }

update/pkg/bootenv/rpi.go

@@ -0,0 +1,267 @@
+package bootenv
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+const (
+	// RPi partition numbers: slot A = partition 2, slot B = partition 3.
+	rpiSlotAPartition = 2
+	rpiSlotBPartition = 3
+
+	defaultBootCounter = 3
+)
+
+// RPiEnv implements BootEnv using Raspberry Pi firmware autoboot.txt.
+type RPiEnv struct {
+	autobootPath string // path to autoboot.txt
+	statusPath   string // path to boot-status file
+}
+
+// NewRPi creates a new RPi-based BootEnv.
+// dir is the directory containing autoboot.txt (typically the boot control
+// partition mount point).
+func NewRPi(dir string) BootEnv {
+	return &RPiEnv{
+		autobootPath: filepath.Join(dir, "autoboot.txt"),
+		statusPath:   filepath.Join(dir, "boot-status"),
+	}
+}
+
+func (r *RPiEnv) ActiveSlot() (string, error) {
+	partNum, err := r.readAllBootPartition()
+	if err != nil {
+		return "", fmt.Errorf("reading active slot: %w", err)
+	}
+	return partNumToSlot(partNum)
+}
+
+func (r *RPiEnv) PassiveSlot() (string, error) {
+	active, err := r.ActiveSlot()
+	if err != nil {
+		return "", err
+	}
+	if active == SlotA {
+		return SlotB, nil
+	}
+	return SlotA, nil
+}
+
+func (r *RPiEnv) BootCounter() (int, error) {
+	status, err := r.readStatus()
+	if err != nil {
+		return -1, err
+	}
+	val, ok := status["boot_counter"]
+	if !ok {
+		return defaultBootCounter, nil
+	}
+	n, err := strconv.Atoi(val)
+	if err != nil {
+		return -1, fmt.Errorf("invalid boot_counter %q: %w", val, err)
+	}
+	return n, nil
+}
+
+func (r *RPiEnv) BootSuccess() (bool, error) {
+	status, err := r.readStatus()
+	if err != nil {
+		return false, err
+	}
+	return status["boot_success"] == "1", nil
+}
+
+func (r *RPiEnv) MarkBootSuccess() error {
+	// Make the current slot permanent by updating [all] boot_partition
+	active, err := r.ActiveSlot()
+	if err != nil {
+		return fmt.Errorf("marking boot success: %w", err)
+	}
+	partNum := slotToPartNum(active)
+	if err := r.writeAllBootPartition(partNum); err != nil {
+		return err
+	}
+	return r.writeStatus(defaultBootCounter, true)
+}
+
+func (r *RPiEnv) ActivateSlot(slot string) error {
+	if slot != SlotA && slot != SlotB {
+		return fmt.Errorf("invalid slot: %q (must be A or B)", slot)
+	}
+	partNum := slotToPartNum(slot)
+	// Update [tryboot] to point to the new slot
+	if err := r.writeTrybootPartition(partNum); err != nil {
+		return err
+	}
+	return r.writeStatus(defaultBootCounter, false)
+}
+
+func (r *RPiEnv) ForceRollback() error {
+	passive, err := r.PassiveSlot()
+	if err != nil {
+		return err
+	}
+	// Swap the [all] boot_partition to the other slot
+	partNum := slotToPartNum(passive)
+	if err := r.writeAllBootPartition(partNum); err != nil {
+		return err
+	}
+	if err := r.writeTrybootPartition(partNum); err != nil {
+		return err
+	}
+	return r.writeStatus(defaultBootCounter, false)
+}
+
+// readAllBootPartition reads the boot_partition value from the [all] section.
+func (r *RPiEnv) readAllBootPartition() (int, error) {
+	sections, err := r.parseAutoboot()
+	if err != nil {
+		return 0, err
+	}
+	val, ok := sections["all"]["boot_partition"]
+	if !ok {
+		return 0, fmt.Errorf("boot_partition not found in [all] section")
+	}
+	return strconv.Atoi(val)
+}
+
+// writeAllBootPartition updates the [all] boot_partition value.
+func (r *RPiEnv) writeAllBootPartition(partNum int) error {
+	sections, err := r.parseAutoboot()
+	if err != nil {
+		return err
+	}
+	if sections["all"] == nil {
+		sections["all"] = make(map[string]string)
+	}
+	sections["all"]["boot_partition"] = strconv.Itoa(partNum)
+	return r.writeAutoboot(sections)
+}
+
+// writeTrybootPartition updates the [tryboot] boot_partition value.
+func (r *RPiEnv) writeTrybootPartition(partNum int) error {
+	sections, err := r.parseAutoboot()
+	if err != nil {
+		return err
+	}
+	if sections["tryboot"] == nil {
+		sections["tryboot"] = make(map[string]string)
+	}
+	sections["tryboot"]["boot_partition"] = strconv.Itoa(partNum)
+	return r.writeAutoboot(sections)
+}
+
+// parseAutoboot reads autoboot.txt into a map of section -> key=value pairs.
+func (r *RPiEnv) parseAutoboot() (map[string]map[string]string, error) {
+	data, err := os.ReadFile(r.autobootPath)
+	if err != nil {
+		return nil, fmt.Errorf("reading autoboot.txt: %w", err)
+	}
+
+	sections := make(map[string]map[string]string)
+	currentSection := ""
+
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
+			currentSection = line[1 : len(line)-1]
+			if sections[currentSection] == nil {
+				sections[currentSection] = make(map[string]string)
+			}
+			continue
+		}
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) == 2 && currentSection != "" {
+			sections[currentSection][strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+		}
+	}
+
+	return sections, nil
+}
+
+// writeAutoboot writes sections back to autoboot.txt.
+// Section order: [all] first, then [tryboot].
+func (r *RPiEnv) writeAutoboot(sections map[string]map[string]string) error {
+	var sb strings.Builder
+
+	// Write [all] section first
+	if all, ok := sections["all"]; ok {
+		sb.WriteString("[all]\n")
+		for k, v := range all {
+			sb.WriteString(k + "=" + v + "\n")
+		}
+	}
+
+	// Write [tryboot] section
+	if tryboot, ok := sections["tryboot"]; ok {
+		sb.WriteString("[tryboot]\n")
+		for k, v := range tryboot {
+			sb.WriteString(k + "=" + v + "\n")
+		}
+	}
+
+	return os.WriteFile(r.autobootPath, []byte(sb.String()), 0o644)
+}
+
+// readStatus reads the boot-status key=value file.
+func (r *RPiEnv) readStatus() (map[string]string, error) {
+	data, err := os.ReadFile(r.statusPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			// Return defaults if status file doesn't exist yet
+			return map[string]string{
+				"boot_counter": strconv.Itoa(defaultBootCounter),
+				"boot_success": "0",
+			}, nil
+		}
+		return nil, fmt.Errorf("reading boot-status: %w", err)
+	}
+
+	status := make(map[string]string)
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) == 2 {
+			status[strings.TrimSpace(parts[0])] = strings.TrimSpace(parts[1])
+		}
+	}
+	return status, nil
+}
+
+// writeStatus writes boot_counter and boot_success to the status file.
+func (r *RPiEnv) writeStatus(counter int, success bool) error {
+	successVal := "0"
+	if success {
+		successVal = "1"
+	}
+	content := fmt.Sprintf("boot_counter=%d\nboot_success=%s\n", counter, successVal)
+	return os.WriteFile(r.statusPath, []byte(content), 0o644)
+}
+
+func partNumToSlot(partNum int) (string, error) {
+	switch partNum {
+	case rpiSlotAPartition:
+		return SlotA, nil
+	case rpiSlotBPartition:
+		return SlotB, nil
+	default:
+		return "", fmt.Errorf("unknown partition number %d (expected %d or %d)", partNum, rpiSlotAPartition, rpiSlotBPartition)
+	}
+}
+
+func slotToPartNum(slot string) int {
+	if slot == SlotB {
+		return rpiSlotBPartition
+	}
+	return rpiSlotAPartition
+}