build: guard INITRAMFS_ARCHIVE in stage_kernel_build for incremental runs

initramfs: ensure essential dirs incl. /home exist during finalize and validate 'home' as essential item

scripts/build.sh

@@ -397,6 +397,17 @@ function main_build_process() {
     
     function stage_kernel_build() {
         local kernel_output="${DIST_DIR}/vmlinuz.efi"
+
+        # Ensure INITRAMFS_ARCHIVE is set even if initramfs_create/test were skipped previously
+        if [[ -z "${INITRAMFS_ARCHIVE:-}" ]]; then
+            local archive_path="${DIST_DIR}/initramfs.cpio.xz"
+            if [[ "${archive_path}" != /* ]]; then
+                archive_path="${PROJECT_ROOT}/${archive_path#./}"
+            fi
+            export INITRAMFS_ARCHIVE="${archive_path}"
+            log_debug "stage_kernel_build: defaulting INITRAMFS_ARCHIVE=${INITRAMFS_ARCHIVE}"
+        fi
+
         kernel_build_with_initramfs "$KERNEL_CONFIG" "$INITRAMFS_ARCHIVE" "$kernel_output"
         export KERNEL_OUTPUT="$kernel_output"
     }

scripts/lib/initramfs.sh

@@ -631,6 +631,14 @@ EOF
         log_info "Branding disabled: leaving /etc/motd, /etc/issue and root password unchanged"
     fi
 
+    # Ensure essential Linux filesystem directories exist (defensive), including /home
+    # Some earlier stages or cleanups may have run in previous builds; enforce presence now.
+    log_info "Ensuring essential directories exist (including /home)"
+    local _ensure_dirs=("dev" "proc" "sys" "tmp" "run" "mnt" "home" "root" "opt" "srv" "media" "media/cdrom" "media/floppy" "media/usb")
+    for _d in "${_ensure_dirs[@]}"; do
+        safe_mkdir "${initramfs_dir}/${_d}"
+    done
+     
     # Ensure ntp.conf exists for hooks. Create only if absent, do not overwrite.
     if [[ ! -f "${initramfs_dir}/etc/ntp.conf" ]]; then
         log_info "Creating ntp.conf with Google NTP servers (absent)"
@@ -735,7 +743,7 @@ function initramfs_create_cpio() {
     local pre_cpio_file_count
     pre_cpio_file_count=$(find "${initramfs_dir}" -mindepth 1 | wc -l || echo "0")
     log_info "Pre-CPIO sanity: ${pre_cpio_file_count} files under ${initramfs_dir}"
-    local _essential_items=("init" "sbin/zinit" "bin/busybox" "etc/zinit" "lib" "usr/bin" "var" "tmp" "proc" "sys" "dev")
+    local _essential_items=("init" "sbin/zinit" "bin/busybox" "etc/zinit" "lib" "usr/bin" "home" "var" "tmp" "proc" "sys" "dev")
     for _item in "${_essential_items[@]}"; do
         if [[ -e "${initramfs_dir}/${_item}" ]]; then
             log_debug "pre-cpio OK: ${_item}"