[SRU] Please bump firmware revision to 8 from jammy

[Dave Jones]

[ Impact ]

The rev 1.4 variant of the 3B+ requires an updated boot firmware, specifically one at least as recent as that in jammy-updates (version 8). This should be back-ported to focal, and preferably bionic to provide support for Core 18 booting on these devices.

[ Test Plan ]

As a closed boot firmware this will need validation on all supported Pis. For bionic, this is the 2B, 3B, 3A+, and 3B+. For focal, this is the 2B, 3B, 3A+, 3B+, and 4B. Because the package includes wifi and bluetooth firmware as well as boot firmware, the following should be verified:

* Ability to boot successfully
* Ability to reboot successfully
* Ability to shutdown successfully
* That wifi can connect successfully on relevant models (all except the 2B)
* That bluetooth can pair successfully on relevant models (all except the 2B)

[ Regression Potential ]

Fairly low; the firmware in question has been in use on all relevant models in jammy for quite some time, so the regression potential for the operation of the firmware itself is low. That said, the wifi and bluetooth firmware still interacts with the kernel, and bionic and focal have different kernel versions to jammy, hence why the operation of these components will still need (re-)verification.

If issues arise they are most likely to come from the fact that linux-firmware-raspi2 was renamed to linux-firmware-raspi in jammy which affected the diversions in the package. This means the backport isn't *entirely* straight-forward and care must be taken to ensure that all relevant files end up in their correct locations with the correct diversions.

[Dave Jones (waveform)]

Test firmware is available in https://launchpad.net/~waveform/+archive/ubuntu/firmware. Please run through these steps for testing:

* Flash current focal server images (armhf and arm64) from http://cdimage.ubuntu.com/releases/20.04.5/release/ to boot media (SD card) for testing

* Boot the media on a model *other than* the 3B+ rev 1.4 (as the current image will not boot on these)

* Once booted and logged in, fully upgrade and reboot system: sudo apt update; sudo apt full-upgrade; sudo reboot

* Once rebooted, add PPA, upgrade and reboot: sudo add-apt-repository ppa:waveform/firmware; sudo apt full-upgrade; sudo reboot

* After ensuring everything is fine (system boots, ethernet, wifi and bluetooth still operate), shut down the Pi: sudo poweroff

* Move boot media to the 3B+ rev 1.4 board and boot the new pi

* Ensure everything is fine (system boots, ethernet, wifi and bluetooth still operate).

[Dave Jones (waveform)]

If the bump enables the new boards to boot we will have to look at a potential point release for focal on the Pi images.

Note to self: because this bump involves a rename of the package (from linux-firmware-raspi2 to linux-firmware-raspi) this will also involve adjusting the seed ... argh, which doesn't exist! The raspi seed was added in groovy; may need to backport that as well to focal for the purposes of rebuild. Can we even build focal images with ubuntu-image? Need to test...

[Kevin Yeh (kevinyeh)]

@Dave, the current focal server image originally can boot on the rev 1.4 rpi3b+, but core20(https://cdimage.ubuntu.com/ubuntu-core/20/stable/current/) can't, so how do I verify the new firmware works?

[Dave Jones (waveform)]

@kevinyeh Oh, then I'm wondering if it is a boot firmware issue at all; the current Core 20 images were generated in January 2023, after the current point release of focal from August 2022, so they should have firmware at least as recent as the focal images.

How far does the boot process get on the rev 1.4? Does it get past the rainbow screen or not?

[Kevin Yeh (kevinyeh)]

@Dave, I didn't see anything displayed on the monitor with core20.
Only see there is a fixed pattern on ACT LED, 4 long flashes first, followed by 7 short flashes.