Document Raspberry Pi 4 firmware update need

[kallisti5]

Bug Report

Running a circa "2023" firmware on your Raspberry Pi 4 results in Talos not booting (with a 4-blink boot)

Description

Trying to boot 1.5.x, 1.6.x, or 1.7.x across multiple microsd cards, all result in 4-short blink boot.

After loading the official raspberry pi 4 Debian image onto an SD card, and running rpi-update, the official image updated the firmware on the Raspberry Pi 4 to a more recent 2024 version.

After completing the above, Talos 1.7.x boots as expected.

Cause

I'm guessing the 2023 firmware doesn't like something about the Talos disk image layout. Maybe the missing GPT secondary partition table copy or something? Unknown

Documentation

Likely needs some documentation in the guide.

If the Talos image fails to boot with a 4-short blink code, after confirming your image was properly written.. try running rpi-update from the official Raspberry Pi debian image to upgrade to the latest firmware.

[kallisti5]

https://www.raspberrypi.com/documentation/computers/os.html#using-rpi-update can be referenced for documentation

[smira]

I have no problem on pretty old RPi (~2021-2022), so the issue might be unique to your hardware. I will move this issue to overlays repo, as RPi support is handled there.

If you have some suggestions for docs, please open a PR.