Bug#1111119: cdrom: Debian CD or Live disk fails if it is not the first bay

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Itamar Perdomo:
> It's 5 CDROM drives in 5 bays,

So the hardware situation is oppulent but not exotic.


> I always have in the bays an emergency
> Debian Live disk, an emergency Alpine disk, one of the current installation
> disk and one of what I want to test which was Debian 13 in this case.
>
> I've now noticed that this error only occurs if there are multiple Debian
> disks in the bays at the same time. I just put other non-Debian disks and
> they worked perfectly.

This sounds like GRUB or the debian-installer picks the wrong Debian CD
in the course of booting Linux or running debian-installer.

I idimly remember that there are searches for the /.disk directory of
media.

  https://codesearch.debian.net/search?q=package%3Adebian-installer+\.disk
yields a GRUB configuration snippet in
  https://codesearch.debian.net/show?file=debian-installer_20250803%2fbuild%2futil%2fefi-image&line=131#L131

  search --file --set=root /.disk/info

I expect that both involved Debian CDs have such a directory.


In an earlier mail of yours i read:
> > Debian just report that there is no modules loaded and al the rest of steps
> > of installer just fails

Above GRUB command might have caused a jump from the right EFI system
partition (i.e. file /boot/grub/efi.img in the ISO) into the wrong
ISO 9660 filesystem with the further equipment of GRUB and Debian.
I'm not sure whether this can cause the symptoms you experience.

Or other parts of the debian-installer might rely on similar searches.

Hopefully Steve McIntyre will have clearer ideas what could possibly go
wrong with two differing bootable Debian CDs.

You could make an experiment in the meantime and try whether it helps
to swap the two Debian CDs between the two drives.
(Regrettably the ever changing /dev/sr numbering of multiple drives in
the Linux kernel could obscure the effect of swapping after GRUB did
its job. But at least during GRUB's reign it could be deterministic.
Maybe the effect is random enough to appear only in 50 % of boot
attempts.)


Have a nice day :)

Thomas