This repository is a bunch of scripts to build SD card images that various single-board computers (SBC) can boot. Emphasis is on pureness; pure Debian and pure mainline U-boot.

Pre-built images ready for download are availble at sd-card-images.johang.se.

The generated SD card images are made up of two separate images:

• boot-BOARD.bin: Boot image that contains partition table, U-Boot and chip-specific code. The boot image will only work on the board it's built for. The filename indicates which board it's built for.
• debian-ARCH-VERSION-PASSWORD.bin: Debian ext4 root filesystem image that contains a complete Debian installation, including kernel, initrd and device tree. This Debian image is generic and will work on all chips and boards with the CPU architecture it's built for. The filename indicates Debian version, CPU architecture and default root password.

These two images are the concatenated to a single image, which is then written to SD card, for example like this:

$ zcat boot-raspberrypi_3b.bin.gz debian-buster-arm64-XXXXXX.bin.gz > sd-card.img
# dd if=sd-card.img of=/dev/sdXXX

To build a boot image for Raspberry Pi 3 B:

docker build -t sd-images https://github.com/johang/sd-card-images.git
mkdir -p /tmp/sd-images
docker run --rm -v /tmp/sd-images:/artifacts sd-images build-boot raspberrypi_3b bcm2837 rpi_3_defconfig aarch64-linux-gnu

The image will end up in /tmp/sd-images on the host.

To build a Debian ext4 root filesystem image for arm64:

docker build -t sd-images https://github.com/johang/sd-card-images.git
mkdir -p /tmp/sd-images
docker run --rm -v /tmp/sd-images:/artifacts sd-images build-debian debian arm64 buster

The image will end up in /tmp/sd-images on the host.