Hello Maxim,

Thanks for your patch! It's hard to provide a reliable abstraction on
top of all the exotic bootloader installation methods existing.

Currently, each bootloader implements two methods:

* bootloader-installer
* bootloader-disk-image-installer

The first one is dedicated to the installation of the bootloader on a
mounted directory, while the second one is meant to work on a disk
device such as "/dev/sda" or directly on a disk-image.

When producing a disk-image with the "raw" type, we are always creating
and populating an ESP partition (see raw-image-type), regardless of the
selected bootloader. In fact, "raw" should be renamed to "hybrid-efi".

The produced image can work on machines with legacy mbr boot or with EFI
boot. Hence, calling "install-grub-efi" like it's done while building
the lightweight-desktop operating-system is useless and fails. The
attached patch fixes it.

You can test it with:

--8<---------------cut here---------------start------------->8---
qemu-system-x86_64 -m 1024 -bios $(guix build ovmf)/share/firmware/ovmf_x64.bin -hda disk.img
--8<---------------cut here---------------end--------------->8---

> +                              ;; Special case: most bootloaders can be copied
> +                              ;; directly at some fixed location on the image
> +                              ;; disk, but when installed to the master boot
> +                              ;; record (MBR), GRUB requires support files
> +                              ;; present under /boot/grub, which is handled by
> +                              ;; its 'installer' procedure.
>                                #:bootloader-installer
> -                              #+(bootloader-installer bootloader)
> +                              #+(if (eq? 'grub (bootloader-name bootloader))
> +                                    (bootloader-installer bootloader)
> +                                    #f)

That would prevent other bootloaders relying on this procedure to work,
such as extlinux.

Thanks,

Mathieu