installing / restoring GRUB in EFI mode
=======================================

   https://wiki.archlinux.org/index.php/GRUB/EFI_examples
It is well known that different motherboard manufactures implement UEFI differently. 
The purpose of this page is to show hardware-specific methods known to work when 
installing / restoring GRUB in EFI mode.


Asus
====
Z68 Family and U47 Family

   # cp esp/EFI/GRUB/grubx64.efi esp/shellx64.efi

After this launch the UEFI Shell from the UEFI setup/menu (in ASUS UEFI BIOS, switch 
to advanced mode, press Exit in the top right corner and choose "Launch EFI shell from 
filesystem device"). The GRUB menu will show up and you can boot into your system. 
Afterwards you can use efibootmgr to setup a menu entry, for example if you have the 
EFI system partition on /dev/sda1:

   # efibootmgr --create --disk /dev/sda --part 1 --write-signature --loader /EFI/GRUB/grubx64.efi --label "GRUB" --verbose


If your motherboard has no such option (or even if it does), you can use UEFI shell to 
create a UEFI boot option for the Arch partition temporarily.
Once you boot into the UEFI shell, add a UEFI boot menu entry:

   Shell> bcfg boot add 0 FS0:\EFI\GRUB\grubx64.efi "GRUB"

where FS0: is the mapping corresponding to the EFI system partition and \EFI\GRUB\grubx64.efi 
is the the from the --bootloader-id from the grub-install command above.
This will temporarily add a UEFI boot option for the next boot to get into Arch. Once in 
Arch, modprobe efivars and confirm that efibootmgr creates no errors (no errors meaning 
you successfully booted in UEFI mode). Then GRUB installation can be performed again 
and should successfully permanently add a boot entry in the UEFI menu.