Comment 113 for bug 1040557

On Thu, Jan 17, 2013 at 08:02:18PM -0000, Val wrote:

> 'modprobe efivars' has no effect. Some googling reveals that in order to
> get it to work, one needs to boot in the UEFI mode; this modprobe
> command will not work while in the BIOS/CMS mode. I am stuck... I can't
> load UEFI because it's not yet installed and I can't install UEFI from
> the CMS mode. Now what? Any ideas?

Right. The only part of the grub install that needs to happen under UEFI
mode is modifying the EFI variables with efibootmgr to configure the boot
menu. Your Ubuntu install is already bootable under UEFI at this point, but
you would need some way to select it for boot. Some UEFI firmware
implementations have an option to browse to a particular file for booting.
Alternatively, you can boot to the GRUB menu from external media, then
reconfigure the grub boot option to point at the installed system instead
(then run grub-install again to trigger the efibootmgr handling, or just
call efibootmgr directly).