iPXE over HTTP boot for Raspberry Pi 4

Requirements:

• 1 x SD card
• 1 x Raspberry Pi 4 (only tested with 8GB model) with power & ethernet

The flow

PLEASE NOTE, THIS IS FOR PROOF OF CONCEPT ONLY AND WE WILL SETUP AN UNSAFE USER ACCOUNT HERE

1. Download flash-eeprom-ubuntu-jammy.img.xz
2. Flash the image to the SD card, f.e. with the official rpi-imager that auto-handles xz decompression.
3. Put the card in the Pi
4. Power it on
5. Wait until the green led is blinking in a consistent pattern – it should only take a few seconds to reach that
6. Power off, remove SD card & power back on
7. Use your imagination or luck to figure out the IP address of the Pi
8. (you may need to wait a minute here, depending on your internet speed)
9. ssh unsafe@x.x.x.x where x.x.x.x is the IP from step 7 and password is unsafe

How it works

Eeprom flasher images contain http boot configuration that point to specific asset in the latest release of this repo – f.e. flash-eeprom-ubuntu-jammy.img.xz -> boot-ubuntu-jammy.img. After flashing the image to rpi eeprom, the Pi will look up for a boot image that was defined in the Makefile.

The boot image contains UEFI stack and an embedded iPXE driver with embedded iPXE boot script. At boot time it chainloads another iPXE script from this repository – it contains the actual boot information, which kernel to use etc. Finally, it uses cloud-init to set up an unsafe user account.