Iron Linux Shield
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ARM64 / aarch64 Architecture • Preview

Iron Linux.
Now on ARM.

Native 64-bit Debian userland, Linux Kernel 6.12, and the Labwc Wayland compositor tuned for the Raspberry Pi 4 Model B.

Download Pi Image (.img.xz)View Checksums & PC Builds
Hardware Target

Raspberry Pi 4 Model B

Optimized for Broadcom BCM2711 quad-core Cortex-A72 @ 1.8GHz. Compatible with 2GB, 4GB, and 8GB memory configurations (4GB+ recommended).

Graphic Stack

VC4 KMS & Wayland

Direct Kernel Mode Setting using dtoverlay=vc4-kms-v3d. Hardware-accelerated OpenGL ES via Mesa directly on Wayland.

First Boot Service

Auto Rootfs Expansion

The included iron-rpi4-firstboot systemd unit automatically grows the root filesystem to fill your entire SD card on first launch.

Step-by-Step

Flashing & Booting the Raspberry Pi 4

You will need a microSD card of at least 16GB capacity (Class 10 / U3 recommended).

Method A: Raspberry Pi Imager

  1. Download Raspberry Pi Imager from raspberrypi.com.
  2. Click Choose OS → scroll down to Use custom.
  3. Select your downloaded iron-linux-rpi4-arm64.img.xz file (no need to unpack it first).
  4. Click Choose Storage and select your microSD card.
  5. Click Write and confirm.

Method B: Terminal (Linux / macOS)

Stream uncompressed blocks directly to the raw block device:

Flash via xzcat + ddbash
xzcat iron-linux-rpi4-arm64.img.xz | sudo dd of=/dev/sdX bs=4M status=progress conv=fsync

Replace /dev/sdX with your actual card device (e.g., /dev/sdb or /dev/mmcblk0).

First Boot

Credentials & Hardware Startup

Default User
iron
Default Password
live
Root Access
sudo (via iron)
Serial Console
115200 baud

On power-on, the bootloader reads config.txt from the FAT32 boot partition, initializes the Broadcom KMS display driver, and launches Plymouth boot splash.

The gtkgreet graphical login appears on your HDMI display. Enter username iron and password live to enter the Labwc session.

Current Maturity & Known Limitations

The Raspberry Pi 4 port of Iron Linux is currently marked as Preview. While the core Wayland desktop, KMS graphics, Ethernet, USB 3.0, and package updates are fully functional:

  • Raspberry Pi 5 is not officially supported yet due to architectural differences in the RP1 I/O controller and kernel requirements.
  • Onboard Wi-Fi and Bluetooth depend on Debian's firmware-brcm80211 package from the non-free-firmware repository.
  • Hardware-accelerated video decoding (V4L2 M2M H.264/HEVC) relies on ffmpeg hardware pipelines; standard Chromium and Firefox ESR use software rendering for complex codecs by default.

Build the Pi Image from Source

You can build the full Raspberry Pi image on any x86-64 Debian or Ubuntu host using QEMU ARM userspace emulation:

Building ARM64 image on hostbash
# Install build tools & ARM64 emulator
sudo apt-get install debootstrap qemu-user-static binfmt-support sfdisk dosfstools

# Clone Iron Linux OS repository
git clone https://github.com/crossainthero-lab/IronLinux.git
cd IronLinux

# Build raw and xz-compressed Raspberry Pi 4 image
sudo ./scripts/build-rpi4-arm64.sh