Fixes <http://issues.guix.gnu.org/44353>.
Every bootloader should try their best to install themselves using only the
MOUNT-POINT and otherwise do nothing. This requirement comes from the
necessity to call INSTALL-GRUB when installing the (non-EFI) GRUB bootloader,
which needs to populate the root file system with extra modules that cannot be
fit in the core.img file, limited in size to 491520 bytes (by the i386-pc
format required for legacy BIOS compatibility).
As introducing bootloader knowledge at the level of the image code is
undesirable, every bootloader should be adapted to support this fall-back for
their installation procedure (TODO).
* gnu/bootloader/grub.scm (install-grub-efi)[efi-dir]: Skip when the EFI-DIR
argument is set to #f.
b0afa3c5f6