Re: [PATCH 6/6] gnu: Add grub-efi.

[Danny Milosavljevic]

Hi,

efibootmgr is trying to add an entry for Linux to the EFI bootmanager and set 
the boot priority order. It won't usefully autoboot without it. That said, 
depending on how good the UEFI implementation on your laptop is you might be 
able to hit a function key on POST and select the image file manually. (There 
has to be a FAT partition which is supposed to contain all the things that the 
bootloader can boot)

The problem is when you boot in legacy BIOS mode you don't have UEFI 
functionality available, including the calls that would modify the boot order 
and boot menu.

The best way would to also boot the GuixSD USB image via UEFI and not MBR. I 
think all you need for that is the image file on the USB stick on a FAT 
partition under \EFI\BOOT\BOOTX64.EFI . So it should be easy to have a dual ISO 
image.

That said, I only have Libreboot personally so I can't help much with it. I 
just had to fix UEFI problems for a customer of mine (two months ago) so it's 
still fresh in my mind.

Note that many UEFI setups have a "Lock Boot Order" option. Make sure it's not 
locked, otherwise it doesn't matter what efibootmgr does - it will just be 
cleared on next reboot.