bug#30311: efi-less grub install fails

[Danny Milosavljevic]

Hi Ricardo,

On Wed, 31 Jan 2018 19:55:58 +0100
Ricardo Wurmus <address@hidden> wrote:

> “guix system init” fails with a configuration file that specifies
> grub-bootloader (not grub-efi-bootloader).
> 
> “grub-install” reports an error about “lib/grub/x86_64-efi/modinfo.sh”
> not being available.  It suggests passing “--target” or “--device”.
> 
> Our invocation of grub-install does not include a “--target” argument.
> Only after I edited it to pass “--target=i386-pc” did “guix system init”
> pass.

Hmm, I wonder what happened here.

We've been very careful to keep grub and grub-efi separate.

The entire directory lib/grub/x86_64-efi shouldn't be available in the
"grub" package output - and I checked on master, it isn't.  Good.

So that leaves automatic target selection as the culprit.

And indeed, there's a call to grub_install_get_default_x86_platform
in util/grub-install.c .  And that checks for availability of
/sys/firmware/efi and if it exists, defaults to EFI.

I think it's a bug in grub to do that for a grub which doesn't have EFI
platform support. :P

We could just always pass i386-pc in install-grub for i386, but then
we lose i386-ieee1275 (which I have never heard anyone using so maybe
not so bad).

Please report a bug with grub...