package linux-image-6.8.0-35-lowlatency 6.8.0-35.35.1 failed to install/upgrade: run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1

[Steve Downey]

Crash while using ubuntustudio-installer on rpi5

ProblemType: Package
DistroRelease: Ubuntu 24.04
Package: linux-image-6.8.0-35-lowlatency 6.8.0-35.35.1
ProcVersionSignature: Ubuntu 6.8.0-1005.5-raspi 6.8.4
Uname: Linux 6.8.0-1005-raspi aarch64
ApportVersion: 2.28.1-0ubuntu3
Architecture: arm64
CasperMD5CheckResult: unknown
CloudArchitecture: aarch64
CloudID: none
CloudName: none
CloudPlatform: none
CloudSubPlatform: config
Date: Sun Jun 23 15:30:54 2024
ErrorMessage: run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
Python3Details: /usr/bin/python3.12, Python 3.12.3, python3-minimal, 3.12.3-0ubuntu1
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.22.6ubuntu6
 apt 2.7.14build2
SourcePackage: initramfs-tools
Title: package linux-image-6.8.0-35-lowlatency 6.8.0-35.35.1 failed to install/upgrade: run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
UpgradeStatus: Upgraded to noble on 2024-06-17 (6 days ago)

[Benjamin Drung (bdrung)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. The relevant dpkg terminal log says:

```
update-initramfs: Generating /boot/initrd.img-6.8.0-35-lowlatency
Using DTB: bcm2712-rpi-5-b.dtb
Couldn't find DTB bcm2712-rpi-5-b.dtb on the following paths: /etc/flash-kernel/dtbs /usr/lib/linux-image-6.8.0-35-lowlatency /lib/firmware/6.8.0-35-lowlatency/device-tree/
Installing into /boot/dtbs/6.8.0-35-lowlatency/./bcm2712-rpi-5-b.dtb
cp: cannot stat '': No such file or directory
run-parts: /etc/initramfs/post-update.d//flash-kernel exited with return code 1
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 1
```

[Dave Jones (waveform)]

The lowlatency kernel isn't supported on the Pi, and flash-kernel won't permit it to be flashed (because you'd be left with an unbootable system).

Ideally the studio installer should detect this and not select the option by default (or better still, disable it), but I'm not sure there's a simple way for them to do that (at least "properly"; it's fairly easy to detect if you're on a Pi, but ideally the installer should be checking the flash-kernel database to see if there's a kernel-flavor limit in place and act accordingly).

I need to have a think about this -- I'm reasonably confident this is a studio installer bug too (so I'll add that as affected), but I suspect flash-kernel needs to grow some facility for exposing the kernel-flavor limits imposed on the running system.

[Steve Downey (sdowney-n)]

To be honest, I was surprised it got as far as it did, once I stopped to think. I suppose I'm used to the tools having some guardrails to keep me from casually asking for the impossible.
Clean up was fairly straightforward, though, just removing the various lowlatency packages.

[Dave Jones (waveform)]

I haven't had the time to try it myself, but I'm guessing the installer *may* well work, provided the lowlatency kernel option is deselected. There may be some amd64-only packages it attempts to pull in though, I'm not sure.

That said a while back I did succeed in hammering together something ubuntu-studio-like on a Pi by overlaying ubuntustudio-desktop on a Pi server install (https://waldorf.waveform.org.uk/2023/the-ubuntu-studio.html), which worked pretty well (and that was on a Pi 4 -- I should retry that on a 5 when I get a mo).