Wip

2026-03-20 08:57:03 +01:00
parent b85f3d1fdd
commit f41cc5aef1
7 changed files with 556 additions and 13 deletions
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,49 @@

 ---

+## V30 2026-03-20 07:50:00
+
+**Add kernel build script, initramfs, and live ISO boot support (Phase 4)**
+
+### Changes:
+- Created `kernel/build-kernel.sh` — automated kernel build script:
+  - Downloads Linux 6.19.9 from cdn.kernel.org (with mirror fallback)
+  - Applies DarkForge config via `make olddefconfig`
+  - Verifies all critical config options (EFI_STUB, NVME, EXT4, PREEMPT, etc.)
+  - Compiles bzImage with `-j32` and KCFLAGS="-march=znver4 -pipe"
+  - Outputs to `kernel/vmlinuz`, `kernel/vmlinuz.efi`, `kernel/System.map`
+  - Installs modules to `kernel/modules/`
+- Updated `kernel/config`:
+  - Added CONFIG_CMDLINE_BOOL=y with serial console (ttyS0,115200n8)
+  - Added CONFIG_CMDLINE_OVERRIDE=n (allows efibootmgr to override at boot)
+  - Added CONFIG_BLK_DEV_INITRD=y (needed for live ISO squashfs boot)
+  - Added CONFIG_SERIAL_8250=y + CONFIG_SERIAL_8250_CONSOLE=y
+- Created `src/iso/initramfs/init` — live ISO init script:
+  - Mounts proc/sys/devtmpfs, scans for DarkForge media on CD/USB/NVMe
+  - Mounts squashfs root, creates tmpfs overlay for writable root
+  - switch_roots into the live system
+  - Falls back to emergency shell if media not found
+- Created `src/iso/build-initramfs.sh` — builds initramfs.cpio.gz from busybox
+- Updated `src/iso/build-iso-arch.sh`:
+  - Now builds initramfs automatically if not present
+  - Includes initramfs in the EFI partition alongside kernel
+  - Creates startup.nsh for UEFI shell fallback
+  - Dynamically sizes the ESP based on kernel + initramfs size
+- Updated `tests/run-tests.sh` QEMU test:
+  - Uses QEMU direct kernel boot (`-kernel` + `-initrd`) when a compiled kernel
+    is available — more reliable than UEFI ISO boot for testing
+  - Falls back to OVMF UEFI boot when no compiled kernel exists
+
+### Plan deviation/changes:
+- Kernel version bumped from 6.19.8 to 6.19.9 (latest 6.19.x stable)
+
+### What is missing/needs polish:
+- Kernel must be compiled by running `bash kernel/build-kernel.sh` on the target machine
+- Once kernel is built, `qemu.kernel_boots` and `qemu.reaches_userspace` should pass
+- Live ISO boot chain: kernel → initramfs → squashfs → overlay → init — needs end-to-end test
+
+---
+
 ## V29 2026-03-20 07:36:03

 **Fix brace expansion failure in ISO build script causing missing directories**
--- a/kernel/build-kernel.sh
+++ b/kernel/build-kernel.sh
@@ -0,0 +1,227 @@
+#!/bin/bash
+# ============================================================================
+# DarkForge Linux — Kernel Build Script
+# ============================================================================
+# Downloads, configures, and compiles the Linux kernel for DarkForge.
+#
+# Prerequisites (Arch Linux):
+#   sudo pacman -S base-devel bc flex bison libelf perl openssl
+#
+# Usage:
+#   cd /path/to/project-root
+#   bash kernel/build-kernel.sh
+#
+# Output:
+#   kernel/vmlinuz              — Compressed kernel (bzImage)
+#   kernel/vmlinuz.efi          — Copy with .efi extension for EFISTUB
+#   kernel/System.map           — Symbol map
+#   kernel/modules/             — Kernel modules (if any)
+#   build/linux-<version>/      — Full kernel source tree (for module builds)
+#
+# Notes:
+#   - Runs as regular user (no sudo needed for compile)
+#   - Uses the config at kernel/config
+#   - Applies 'make olddefconfig' to fill in defaults for unspecified options
+#   - Builds with -j32 (16C/32T)
+# ============================================================================
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
+
+# --- Configuration -----------------------------------------------------------
+KERNEL_VERSION="6.19.9"
+KERNEL_MAJOR="6.19"
+KERNEL_URL="https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-${KERNEL_VERSION}.tar.xz"
+KERNEL_SIGN_URL="${KERNEL_URL}.sign"
+BUILD_DIR="${PROJECT_ROOT}/build"
+KERNEL_SRC="${BUILD_DIR}/linux-${KERNEL_VERSION}"
+CONFIG_FILE="${SCRIPT_DIR}/config"
+JOBS=32
+
+RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; CYAN='\033[0;36m'; NC='\033[0m'
+info() { echo -e "${CYAN}>>> $1${NC}"; }
+ok()   { echo -e "${GREEN}>>> $1${NC}"; }
+warn() { echo -e "${YELLOW}!!! $1${NC}"; }
+die()  { echo -e "${RED}!!! $1${NC}"; exit 1; }
+
+# --- Preflight ---------------------------------------------------------------
+info "DarkForge Kernel Builder — Linux ${KERNEL_VERSION}"
+echo ""
+
+# Check required tools
+for tool in gcc make flex bison bc perl; do
+    command -v "$tool" >/dev/null 2>&1 || die "Missing: $tool — install with pacman"
+done
+
+# Check for libelf headers (needed for CONFIG_BPF_SYSCALL, etc.)
+if ! pkg-config --exists libelf 2>/dev/null; then
+    warn "libelf not found — install with: sudo pacman -S libelf"
+    warn "Continuing anyway (may fail if CONFIG_BPF_SYSCALL=y)"
+fi
+
+# Check for openssl headers (needed for module signing)
+if ! pkg-config --exists openssl 2>/dev/null && ! [ -f /usr/include/openssl/opensslv.h ]; then
+    warn "OpenSSL headers not found — install with: sudo pacman -S openssl"
+fi
+
+# --- Download kernel source --------------------------------------------------
+mkdir -p "${BUILD_DIR}"
+
+TARBALL="${BUILD_DIR}/linux-${KERNEL_VERSION}.tar.xz"
+if [ -f "$TARBALL" ]; then
+    info "Kernel tarball already downloaded: ${TARBALL}"
+else
+    info "Downloading Linux ${KERNEL_VERSION}..."
+    # Try cdn.kernel.org first, then mirrors
+    for url in \
+        "https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-${KERNEL_VERSION}.tar.xz" \
+        "https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/linux-${KERNEL_VERSION}.tar.xz" \
+        "https://mirror.aarnet.edu.au/pub/ftp.kernel.org/linux/kernel/v6.x/linux-${KERNEL_VERSION}.tar.xz"; do
+        if curl --connect-timeout 15 -fL# -o "$TARBALL" "$url" 2>&1; then
+            ok "Downloaded from ${url}"
+            break
+        else
+            warn "Failed: ${url}"
+            rm -f "$TARBALL"
+        fi
+    done
+fi
+
+[ -f "$TARBALL" ] || die "Failed to download kernel tarball"
+
+# Verify tarball is valid
+if ! xz -t "$TARBALL" 2>/dev/null; then
+    die "Kernel tarball is corrupt — delete ${TARBALL} and re-run"
+fi
+
+# --- Extract kernel source ---------------------------------------------------
+if [ -d "$KERNEL_SRC" ] && [ -f "$KERNEL_SRC/Makefile" ]; then
+    info "Kernel source already extracted: ${KERNEL_SRC}"
+else
+    info "Extracting Linux ${KERNEL_VERSION}..."
+    tar -xf "$TARBALL" -C "${BUILD_DIR}"
+    [ -d "$KERNEL_SRC" ] || die "Expected directory ${KERNEL_SRC} not found after extraction"
+    ok "Extracted to ${KERNEL_SRC}"
+fi
+
+# --- Apply DarkForge config --------------------------------------------------
+info "Applying DarkForge kernel config..."
+
+# Copy our config
+cp "$CONFIG_FILE" "${KERNEL_SRC}/.config"
+
+# Update version target in config header comment (informational only)
+# The actual version comes from the kernel source, not the config
+
+# Run olddefconfig to fill in all unspecified options with defaults
+# This is critical — our config only specifies ~176 options out of thousands
+cd "$KERNEL_SRC"
+make olddefconfig
+
+ok "Config applied — $(grep -c '=y\|=m' .config) options enabled"
+
+# Verify critical options survived olddefconfig
+CRITICAL_OPTS=(
+    "CONFIG_EFI_STUB=y"
+    "CONFIG_BLK_DEV_NVME=y"
+    "CONFIG_EXT4_FS=y"
+    "CONFIG_PREEMPT=y"
+    "CONFIG_MODULES=y"
+    "CONFIG_DRM=y"
+    "CONFIG_R8169=y"
+    "CONFIG_EFI=y"
+)
+FAIL=0
+for opt in "${CRITICAL_OPTS[@]}"; do
+    key="${opt%%=*}"
+    if ! grep -q "^${opt}$" .config; then
+        warn "CRITICAL: ${opt} not set in final config!"
+        FAIL=1
+    fi
+done
+if [ "$FAIL" -eq 1 ]; then
+    die "Critical config options missing after olddefconfig — review .config"
+fi
+ok "All critical config options verified"
+
+# --- Compile -----------------------------------------------------------------
+info "Compiling Linux ${KERNEL_VERSION} with -j${JOBS}..."
+info "This will take a few minutes on 16C/32T..."
+echo ""
+
+# Set DarkForge compiler flags for kernel build
+# Note: kernel has its own CFLAGS handling; -march is passed via KCFLAGS
+# The kernel's CONFIG_MZEN4 handles most CPU-specific codegen
+KCFLAGS="-march=znver4 -pipe"
+# znver4 because znver5 may not be fully supported by all kernel assembly
+# TODO: test znver5 when compiler+kernel support is confirmed
+
+START_TIME=$(date +%s)
+
+make -j${JOBS} KCFLAGS="$KCFLAGS" bzImage 2>&1 | tail -20
+
+END_TIME=$(date +%s)
+ELAPSED=$((END_TIME - START_TIME))
+
+if [ -f "arch/x86/boot/bzImage" ]; then
+    ok "Kernel compiled in ${ELAPSED}s"
+else
+    die "Kernel compilation failed — check output above"
+fi
+
+# Build modules (for any =m options)
+info "Building kernel modules..."
+make -j${JOBS} modules 2>&1 | tail -5
+ok "Modules built"
+
+# --- Install outputs ---------------------------------------------------------
+info "Installing kernel outputs..."
+
+# Copy bzImage
+cp arch/x86/boot/bzImage "${SCRIPT_DIR}/vmlinuz"
+cp arch/x86/boot/bzImage "${SCRIPT_DIR}/vmlinuz.efi"
+ok "Kernel: ${SCRIPT_DIR}/vmlinuz ($(du -h "${SCRIPT_DIR}/vmlinuz" | cut -f1))"
+
+# Copy System.map
+cp System.map "${SCRIPT_DIR}/System.map"
+
+# Install modules to a staging directory
+MODULES_DIR="${SCRIPT_DIR}/modules"
+rm -rf "$MODULES_DIR"
+make INSTALL_MOD_PATH="$MODULES_DIR" modules_install 2>&1 | tail -3
+ok "Modules installed to ${MODULES_DIR}"
+
+# Verify the kernel is a valid EFI application
+if file "${SCRIPT_DIR}/vmlinuz" | grep -q "bzImage"; then
+    ok "Kernel is a valid bzImage"
+elif file "${SCRIPT_DIR}/vmlinuz" | grep -q "EFI\|PE32"; then
+    ok "Kernel is a valid EFI binary"
+else
+    warn "Kernel type: $(file "${SCRIPT_DIR}/vmlinuz")"
+    warn "May not boot via EFISTUB — verify manually"
+fi
+
+# --- Summary -----------------------------------------------------------------
+echo ""
+echo "============================================================================"
+echo -e "${GREEN}  DarkForge Kernel Build Complete${NC}"
+echo "============================================================================"
+echo ""
+echo "  Version:    Linux ${KERNEL_VERSION}-darkforge"
+echo "  Kernel:     ${SCRIPT_DIR}/vmlinuz"
+echo "  Kernel EFI: ${SCRIPT_DIR}/vmlinuz.efi"
+echo "  System.map: ${SCRIPT_DIR}/System.map"
+echo "  Modules:    ${MODULES_DIR}/"
+echo "  Source:     ${KERNEL_SRC}/"
+echo ""
+echo "  Compile time: ${ELAPSED}s"
+echo "  Kernel size:  $(du -h "${SCRIPT_DIR}/vmlinuz" | cut -f1)"
+echo ""
+echo "  Next steps:"
+echo "    1. Rebuild ISO: sudo bash src/iso/build-iso-arch.sh"
+echo "    2. Test in QEMU: see tests/run-tests.sh"
+echo "    3. For real hardware: copy vmlinuz.efi to ESP as /EFI/Linux/vmlinuz.efi"
+echo ""
+echo "============================================================================"
--- a/kernel/config
+++ b/kernel/config
@@ -443,3 +443,26 @@ CONFIG_FANOTIFY=y

 CONFIG_EXPERT=y
 # Enable expert mode to access all configuration options
+
+# =============================================================================
+# KERNEL COMMAND LINE
+# =============================================================================
+
+CONFIG_CMDLINE_BOOL=y
+CONFIG_CMDLINE="console=tty0 console=ttyS0,115200n8"
+CONFIG_CMDLINE_OVERRIDE=n
+# Embedded default command line for EFISTUB boot:
+# - console=tty0: keep framebuffer console for real hardware
+# - console=ttyS0: serial console for QEMU testing and debugging
+# CMDLINE_OVERRIDE=n allows efibootmgr to append/override at boot time
+# Root device is set per-boot:
+#   Live ISO: root= is handled by the initramfs (mounts squashfs)
+#   Installed: efibootmgr -u "root=/dev/nvme0n1p2 rootfstype=ext4"
+
+CONFIG_BLK_DEV_INITRD=y
+# Initramfs support — needed for live ISO boot (squashfs overlay)
+# Installed system boots without initramfs (NVMe + ext4 are built-in)
+
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+# Serial console support — needed for QEMU testing and remote debugging
--- a/src/iso/build-initramfs.sh
+++ b/src/iso/build-initramfs.sh
@@ -0,0 +1,80 @@
+#!/bin/bash
+# ============================================================================
+# DarkForge Linux — Build Initramfs for Live ISO
+# ============================================================================
+# Creates a minimal initramfs containing busybox and the init script.
+# The initramfs is used by the live ISO to mount the squashfs root.
+#
+# Output: src/iso/initramfs.cpio.gz (embedded in the ISO alongside the kernel)
+#
+# Usage:
+#   bash src/iso/build-initramfs.sh
+# ============================================================================
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "${SCRIPT_DIR}/../.." && pwd)"
+INITRAMFS_DIR=$(mktemp -d /tmp/darkforge-initramfs-XXXXX)
+OUTPUT="${SCRIPT_DIR}/initramfs.cpio.gz"
+
+RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; CYAN='\033[0;36m'; NC='\033[0m'
+info() { echo -e "${CYAN}>>> $1${NC}"; }
+ok()   { echo -e "${GREEN}>>> $1${NC}"; }
+warn() { echo -e "${YELLOW}!!! $1${NC}"; }
+die()  { echo -e "${RED}!!! $1${NC}"; exit 1; }
+
+info "Building DarkForge initramfs..."
+
+# Create directory structure
+mkdir -p "${INITRAMFS_DIR}"/{bin,sbin,dev,proc,sys,media,rootfs,overlay,tmpfs,newroot,etc,tmp}
+
+# Find busybox
+BUSYBOX=""
+if command -v busybox >/dev/null 2>&1; then
+    BUSYBOX="$(which busybox)"
+elif [ -f /usr/bin/busybox ]; then
+    BUSYBOX="/usr/bin/busybox"
+fi
+
+if [ -z "$BUSYBOX" ]; then
+    die "busybox not found — install with: sudo pacman -S busybox"
+fi
+
+# Copy busybox and create symlinks for all needed applets
+cp "$BUSYBOX" "${INITRAMFS_DIR}/bin/busybox"
+chmod +x "${INITRAMFS_DIR}/bin/busybox"
+
+# Create symlinks for commands used by the init script
+for cmd in sh mount umount mkdir echo sleep cat switch_root exec \
+           mount.squashfs losetup mdev modprobe; do
+    ln -sf busybox "${INITRAMFS_DIR}/bin/$cmd"
+done
+
+# switch_root is typically in /sbin
+ln -sf ../bin/busybox "${INITRAMFS_DIR}/sbin/switch_root"
+
+# Copy the init script
+cp "${SCRIPT_DIR}/initramfs/init" "${INITRAMFS_DIR}/init"
+chmod +x "${INITRAMFS_DIR}/init"
+
+# Create essential device nodes
+mknod -m 622 "${INITRAMFS_DIR}/dev/console" c 5 1 2>/dev/null || true
+mknod -m 666 "${INITRAMFS_DIR}/dev/null" c 1 3 2>/dev/null || true
+mknod -m 666 "${INITRAMFS_DIR}/dev/zero" c 1 5 2>/dev/null || true
+mknod -m 666 "${INITRAMFS_DIR}/dev/tty" c 5 0 2>/dev/null || true
+
+# Create the cpio archive
+info "Creating cpio archive..."
+cd "${INITRAMFS_DIR}"
+find . -print0 | cpio --null --create --format=newc 2>/dev/null | gzip -9 > "$OUTPUT"
+
+# Cleanup
+rm -rf "${INITRAMFS_DIR}"
+
+SIZE=$(du -h "$OUTPUT" | cut -f1)
+ok "Initramfs created: ${OUTPUT} (${SIZE})"
+echo ""
+echo "  To use with the ISO:"
+echo "    The build-iso-arch.sh script will automatically include this initramfs."
+echo ""
--- a/src/iso/build-iso-arch.sh
+++ b/src/iso/build-iso-arch.sh
@@ -210,6 +210,19 @@ done
 chmod -R a+rX "${ROOTFS}/var/lib/dpack/repos/"
 ls -la "${ROOTFS}/var/lib/dpack/repos/" || true

+# --- Build initramfs for live boot -------------------------------------------
+INITRAMFS_PATH="${SCRIPT_DIR}/initramfs.cpio.gz"
+if [ ! -f "$INITRAMFS_PATH" ]; then
+    info "Building initramfs..."
+    bash "${SCRIPT_DIR}/build-initramfs.sh"
+fi
+
+if [ -f "$INITRAMFS_PATH" ]; then
+    ok "Initramfs: ${INITRAMFS_PATH} ($(du -h "$INITRAMFS_PATH" | cut -f1))"
+else
+    warn "No initramfs — live ISO will not be able to mount squashfs root"
+fi
+
 # --- Install kernel ----------------------------------------------------------
 KERNEL_PATH=""
 for kp in "${PROJECT_ROOT}/kernel/vmlinuz" "${PROJECT_ROOT}/build/vmlinuz" /boot/vmlinuz-linux; do
@@ -220,8 +233,15 @@ for kp in "${PROJECT_ROOT}/kernel/vmlinuz" "${PROJECT_ROOT}/build/vmlinuz" /boot
 done

 if [ -n "$KERNEL_PATH" ]; then
+    # Copy kernel to ISO
    cp "$KERNEL_PATH" "${ISO_DIR}/EFI/BOOT/BOOTX64.EFI"
    ok "Kernel: ${KERNEL_PATH}"
+
+    # Also copy initramfs alongside kernel in the ISO
+    if [ -f "$INITRAMFS_PATH" ]; then
+        cp "$INITRAMFS_PATH" "${ISO_DIR}/LiveOS/initramfs.img"
+        ok "Initramfs copied to ISO"
+    fi
 else
    warn "No kernel found — ISO will not be bootable!"
    warn "Build the kernel first (Phase 4) or copy vmlinuz to kernel/vmlinuz"
@@ -241,12 +261,34 @@ ok "squashfs: $(du -sh "${ISO_DIR}/LiveOS/rootfs.img" | cut -f1)"
 info "Creating EFI boot image..."
 # efiboot.img MUST be inside ISO_DIR so xorriso can find it via -e flag
 ESP_IMG="${ISO_DIR}/efiboot.img"
-ESP_SIZE=8192  # 8MB
+# Size the ESP large enough for kernel + initramfs
+KERNEL_SIZE=$(stat -c%s "${ISO_DIR}/EFI/BOOT/BOOTX64.EFI" 2>/dev/null || echo "1048576")
+INITRD_SIZE=0
+if [ -f "${ISO_DIR}/LiveOS/initramfs.img" ]; then
+    INITRD_SIZE=$(stat -c%s "${ISO_DIR}/LiveOS/initramfs.img")
+fi
+# ESP size: kernel + initramfs + 4MB padding, minimum 8MB
+ESP_SIZE=$(( (KERNEL_SIZE + INITRD_SIZE + 4194304) / 1024 ))
+[ "$ESP_SIZE" -lt 8192 ] && ESP_SIZE=8192
+
 dd if=/dev/zero of="${ESP_IMG}" bs=1K count=${ESP_SIZE} 2>/dev/null
 mkfs.fat -F 12 "${ESP_IMG}" >/dev/null
 mmd -i "${ESP_IMG}" ::/EFI ::/EFI/BOOT
 mcopy -i "${ESP_IMG}" "${ISO_DIR}/EFI/BOOT/BOOTX64.EFI" ::/EFI/BOOT/BOOTX64.EFI

+# Include initramfs in the EFI partition if available
+if [ -f "${ISO_DIR}/LiveOS/initramfs.img" ]; then
+    mcopy -i "${ESP_IMG}" "${ISO_DIR}/LiveOS/initramfs.img" ::/EFI/BOOT/initramfs.img
+    # Create a startup.nsh script for UEFI shell fallback
+    STARTUP_NSH=$(mktemp)
+    echo '\EFI\BOOT\BOOTX64.EFI initrd=\EFI\BOOT\initramfs.img' > "$STARTUP_NSH"
+    mcopy -i "${ESP_IMG}" "$STARTUP_NSH" ::/startup.nsh
+    rm -f "$STARTUP_NSH"
+    ok "EFI boot image includes kernel + initramfs (ESP: $((ESP_SIZE/1024))MB)"
+else
+    ok "EFI boot image: kernel only (no initramfs)"
+fi
+
 # --- Build ISO ----------------------------------------------------------------
 info "Building ISO..."
 xorriso -as mkisofs \
--- a/src/iso/initramfs/init
+++ b/src/iso/initramfs/init
@@ -0,0 +1,101 @@
+#!/bin/sh
+# ============================================================================
+# DarkForge Linux — Live ISO Initramfs Init Script
+# ============================================================================
+# This script runs as PID 1 from the initramfs during live ISO boot.
+# It finds the ISO media, mounts the squashfs, sets up an overlay, and
+# switch_roots into the live system.
+#
+# Boot flow:
+#   UEFI → EFISTUB kernel → initramfs (this script) → switch_root → /sbin/init
+# ============================================================================
+
+# Mount essential virtual filesystems
+mount -t proc none /proc
+mount -t sysfs none /sys
+mount -t devtmpfs none /dev
+
+# Enable kernel messages on console
+echo 1 > /proc/sys/kernel/printk
+
+echo ""
+echo "  DarkForge Linux — Live Boot"
+echo "  Searching for installation media..."
+echo ""
+
+# Wait for devices to settle
+sleep 2
+
+# Try to find the DarkForge ISO media
+# The ISO has a LiveOS/rootfs.img squashfs file
+MEDIA_FOUND=0
+MEDIA_MNT="/media"
+ROOTFS_MNT="/rootfs"
+OVERLAY_MNT="/overlay"
+
+mkdir -p "$MEDIA_MNT" "$ROOTFS_MNT" "$OVERLAY_MNT"
+
+# Check CD-ROM devices and USB drives
+for attempt in 1 2 3 4 5; do
+    for dev in /dev/sr0 /dev/sr1 /dev/sda /dev/sda1 /dev/sdb /dev/sdb1 \
+               /dev/nvme0n1p1 /dev/nvme1n1p1 /dev/vda /dev/vda1; do
+        [ -b "$dev" ] || continue
+
+        if mount -o ro "$dev" "$MEDIA_MNT" 2>/dev/null; then
+            if [ -f "$MEDIA_MNT/LiveOS/rootfs.img" ]; then
+                echo "  Found DarkForge media on ${dev}"
+                MEDIA_FOUND=1
+                break 2
+            fi
+            umount "$MEDIA_MNT" 2>/dev/null
+        fi
+    done
+    echo "  Attempt ${attempt}/5 — waiting for devices..."
+    sleep 2
+done
+
+if [ "$MEDIA_FOUND" -eq 0 ]; then
+    echo ""
+    echo "  ERROR: Could not find DarkForge installation media!"
+    echo "  Make sure the ISO is written to a USB drive or mounted as CD-ROM."
+    echo ""
+    echo "  Dropping to emergency shell..."
+    exec /bin/sh
+fi
+
+# Mount the squashfs root filesystem
+echo "  Mounting squashfs root filesystem..."
+if ! mount -t squashfs -o ro "$MEDIA_MNT/LiveOS/rootfs.img" "$ROOTFS_MNT" 2>/dev/null; then
+    echo "  ERROR: Failed to mount squashfs!"
+    echo "  Dropping to emergency shell..."
+    exec /bin/sh
+fi
+
+# Set up tmpfs overlay for writable root
+echo "  Setting up writable overlay..."
+mkdir -p /tmpfs
+mount -t tmpfs -o size=75% tmpfs /tmpfs
+mkdir -p /tmpfs/upper /tmpfs/work
+
+# Mount overlayfs: squashfs (read-only lower) + tmpfs (writable upper)
+mkdir -p /newroot
+if mount -t overlay overlay -o "lowerdir=${ROOTFS_MNT},upperdir=/tmpfs/upper,workdir=/tmpfs/work" /newroot 2>/dev/null; then
+    echo "  Overlay root mounted (squashfs + tmpfs)"
+else
+    # Fallback: if overlay not available, bind-mount the squashfs directly
+    echo "  WARNING: overlayfs not available, root will be read-only"
+    mount --bind "$ROOTFS_MNT" /newroot
+fi
+
+# Move virtual filesystems into the new root
+mkdir -p /newroot/proc /newroot/sys /newroot/dev /newroot/media
+mount --move /proc /newroot/proc
+mount --move /sys /newroot/sys
+mount --move /dev /newroot/dev
+mount --move "$MEDIA_MNT" /newroot/media
+
+echo "  Switching to live root filesystem..."
+echo ""
+
+# Switch to the real root and exec init
+exec switch_root /newroot /sbin/init
--- a/tests/run-tests.sh
+++ b/tests/run-tests.sh
@@ -869,18 +869,45 @@ if [ "$QUICK_MODE" = false ] && [ -n "${OVMF_PATH:-}" ] && [ -f "${ISO}" ]; then
        OVMF_FLAGS="-bios ${OVMF_PATH}"
    fi

-    timeout 60 qemu-system-x86_64 \
-        ${KVM_FLAG} \
-        -m 2G \
-        -smp 2 \
-        ${OVMF_FLAGS} \
-        -cdrom "$ISO" \
-        -drive file="$QEMU_DISK",format=qcow2,if=virtio \
-        -nographic \
-        -serial mon:stdio \
-        -no-reboot \
-        2>"${LOG_DIR}/qemu-stderr.log" | head -200 > "${LOG_DIR}/qemu-output.log" &
-    QEMU_PID=$!
+    # Check if we have a real kernel for direct boot (more reliable than UEFI ISO in QEMU)
+    HAS_KERNEL=false
+    [ -f "${PROJECT_ROOT}/kernel/vmlinuz" ] && HAS_KERNEL=true
+
+    INITRD_FLAGS=""
+    [ -f "${PROJECT_ROOT}/src/iso/initramfs.cpio.gz" ] && \
+        INITRD_FLAGS="-initrd ${PROJECT_ROOT}/src/iso/initramfs.cpio.gz"
+
+    if [ "$HAS_KERNEL" = true ]; then
+        echo "  Using direct kernel boot (kernel + initramfs)..."
+        timeout 60 qemu-system-x86_64 \
+            ${KVM_FLAG} \
+            -m 2G \
+            -smp 2 \
+            -kernel "${PROJECT_ROOT}/kernel/vmlinuz" \
+            ${INITRD_FLAGS} \
+            -append "console=ttyS0,115200n8" \
+            -cdrom "$ISO" \
+            -drive file="$QEMU_DISK",format=qcow2,if=virtio \
+            -nographic \
+            -serial mon:stdio \
+            -no-reboot \
+            2>"${LOG_DIR}/qemu-stderr.log" | head -200 > "${LOG_DIR}/qemu-output.log" &
+        QEMU_PID=$!
+    else
+        echo "  Using UEFI ISO boot (no compiled kernel found)..."
+        timeout 60 qemu-system-x86_64 \
+            ${KVM_FLAG} \
+            -m 2G \
+            -smp 2 \
+            ${OVMF_FLAGS} \
+            -cdrom "$ISO" \
+            -drive file="$QEMU_DISK",format=qcow2,if=virtio \
+            -nographic \
+            -serial mon:stdio \
+            -no-reboot \
+            2>"${LOG_DIR}/qemu-stderr.log" | head -200 > "${LOG_DIR}/qemu-output.log" &
+        QEMU_PID=$!
+    fi

    sleep 60
    kill $QEMU_PID 2>/dev/null