diff --git a/build/scripts/inject-kubesolo.sh b/build/scripts/inject-kubesolo.sh
index 97a7236..960e8eb 100755
--- a/build/scripts/inject-kubesolo.sh
+++ b/build/scripts/inject-kubesolo.sh
@@ -84,10 +84,15 @@ if [ "$INJECT_ARCH" = "arm64" ] && [ -x /bin/busybox ]; then
     fi
 fi
 
-# Init stages
+# Init stages — copy NN-name.sh files only. functions.sh is a shared library
+# (sourced by init.sh proper), not a numbered stage; if it ends up in init.d
+# the main loop will try to run it as a stage and fail.
 mkdir -p "$ROOTFS/usr/lib/kubesolo-os/init.d"
 for stage in "$PROJECT_ROOT"/init/lib/*.sh; do
     [ -f "$stage" ] || continue
+    case "$(basename "$stage")" in
+        functions.sh) continue ;;
+    esac
     cp "$stage" "$ROOTFS/usr/lib/kubesolo-os/init.d/"
     chmod +x "$ROOTFS/usr/lib/kubesolo-os/init.d/$(basename "$stage")"
 done
diff --git a/init/lib/30-kernel-modules.sh b/init/lib/30-kernel-modules.sh
index 3a0c601..bf4bca7 100755
--- a/init/lib/30-kernel-modules.sh
+++ b/init/lib/30-kernel-modules.sh
@@ -16,7 +16,11 @@ while IFS= read -r mod; do
     case "$mod" in
         '#'*|'') continue ;;
     esac
-    mod="$(echo "$mod" | tr -d '[:space:]')"
+    # NOTE: do NOT use tr -d '[:space:]' — Ubuntu's busybox-static 1.30.1 (used
+    # in the ARM64 rootfs override) doesn't parse POSIX char classes and treats
+    # them as a literal set, deleting [, :, s, p, a, c, e, ]. Use explicit
+    # whitespace chars instead so the same script works under any tr.
+    mod="$(printf '%s' "$mod" | tr -d ' \t\r\n')"
     if modprobe "$mod" 2>/dev/null; then
         LOADED=$((LOADED + 1))
     else
diff --git a/init/lib/40-sysctl.sh b/init/lib/40-sysctl.sh
index 5869090..074820e 100755
--- a/init/lib/40-sysctl.sh
+++ b/init/lib/40-sysctl.sh
@@ -8,8 +8,11 @@ for conf in /etc/sysctl.d/*.conf; do
         case "$key" in
             '#'*|'') continue ;;
         esac
-        key="$(echo "$key" | tr -d '[:space:]')"
-        value="$(echo "$value" | tr -d '[:space:]')"
+        # NOTE: do NOT use tr -d '[:space:]' — see 30-kernel-modules.sh for the
+        # rationale. Use explicit whitespace chars so this works under
+        # Ubuntu's busybox-static tr too.
+        key="$(printf '%s' "$key" | tr -d ' \t\r\n')"
+        value="$(printf '%s' "$value" | tr -d ' \t\r\n')"
         if [ -n "$key" ] && [ -n "$value" ]; then
             sysctl -w "${key}=${value}" >/dev/null 2>&1 || \
                 log_warn "Failed to set sysctl: ${key}=${value}"