flash-kernel still using u-boot for Raspberry Pi

[Markus Birth]

The Raspberry Pi firmware can boot a Linux kernel perfectly fine with these settings in config.txt:

kernel=vmlinuz
initramfs initrd.img followkernel

(Note that the space between "initramfs" and "initrd.img" is intentional!)

So there's no actual need to use u-boot anymore. Also, at the moment, there's bug #1791466 with u-boot on the Raspberry Pi 3.

Removing the u-boot bootloader and boot scripts would clean things up a lot. Also removing that shouldn't have any effect on existing installations because the boot script doesn't change anyways.

[Dave Jones (waveform)]

Sorry, we'll be sticking with u-boot for the foreseeable future. Partly this is because it keeps things (somewhat) consistent between the core and classic images, but also keeps things consistent between RPi and Ubuntu images for other embedded platforms. Were we to remove u-boot from the RPi images, it would make them a special case among all such images (it's also worth noting we may start inheriting u-boot configuration from Debian upstream in future; Debian also uses u-boot although we currently override their configuration for RPi).

[Dave Jones (waveform)]

Ha! This aged well! I finally managed to switch us away from using u-boot (at least on the classic images, Ubuntu Pi for Server and Desktop, though not on Core) during the Groovy (20.10) release, but somehow managed to forget about closing this bug!