Bug#966575: grub-pc: error: symbol `grub_calloc' not found.

[Colin Watson]

On Sat, Aug 01, 2020 at 01:23:30AM +0200, MichaIng wrote:
> we face the same issue whenever a ready-to-run image has been created and
> booted from a different device.
> 
> From what we found, the Debian installer (or the grub install/config
> scripts) stores the hardware ID of the drive to debconf database, if one is
> available. Of course on a different machine this identifier and the related
> /dev/disk/by-id/ path is invalid. On VirtualBox and non-virtual PCs this is
> usually the case, on VMware on the other hand, ho hardware identifier
> exists, hence /dev/sda is stored there which is still valid when importing
> the same image to other VMware machines.

Indeed.

> I suggest to do the grub target check on `preinst` and skip/fail with error
> code if the debconf entry is invalid. It is better to skip or break the
> package upgrade and force admins to check/run manually then letting them
> running into a unbootable system.

That's fairly close to one of my suggestions in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966575#102.  It's not
necessary to move things to the preinst to make this work; it just needs
to be checked a bit more thoroughly before the postinst runs
grub-install.

> Otherwise elegant would be a scan to find the matching grub instance, but
> not sure how easy this is. At least the bootloader locations are fixed?

In principle it's impossible.  In practice it may be possible to do some
degree of guesswork; that's one of my other suggestions in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966575#102. :-)  We do
have to be pretty conservative though, as going overboard is likely to
break some multiboot setups.

-- 
Colin Watson (he/him)                              [cjwatson at debian.org]