Bug#1102160: upgrade-reports: Bookworm to Trixie [amd64][EFI] initramfs unpacking failed invalid magic at start of compressed archive

[Pascal Hambourg]

On 19/04/2025 at 08:02, Martin-Éric Racine wrote:
> la 19.4.2025 klo 8.43 Felix Zielcke (fzielcke at z-51.de) kirjoitti:
>> Am Freitag, dem 18.04.2025 um 21:17 +0300 schrieb Martin-Éric Racine:
>>> pe 18.4.2025 klo 19.39 Felix Zielcke (fzielcke at z-51.de) kirjoitti:
>>>>
>>>> You could though test the fs drivers of it with grub-mount:
>>>>
>>>> grub-mount /dev/sda2 /mnt (replace sda2 with your / partition)
>>>> sha1sum /mnt/@rootfs/boot/initrd.img-6.12.20-amd64
>>>> sha1sum /@rootfs/boot/initrd.img-6.12.20-amd64
>>>>
>>>> both commands should output the same hash sum.
>>>> And yes, this is safe with a mounted fs because the GRUB fs code is
>>>> 100% complete read-only.
> 
> Same checksum. However, manually executing this tells us nothing. It's
> performed on a filesystem that's already available. It doesn't
> simulate GRUB attempting to cold mount a system on a booting host.

It does not matter whether the filesystem is already mounted and 
available. grub-mount does not use the kernel filesystem layer, it reads 
directly the partition (or disk ?) block devices and uses GRUB's own 
filesystem drivers.

> There seems to be two issues here:
> 
> 1) A magic error upon loading initrd. It also affects the Trixie
> rescue mode via UEFI (but not via BIOS).

It is unclear what you mean here. Does it affect
- boot trixie installer kernel and initramfs
or
- boot your system kernel and initramfs from trixie installer GRUB ?

> 2) fuseblk reporting an unsupported subvol option on Trixie.

I already explained this is a red herring.