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UEFI Notes

I learned (or relearned?) a bit about UEFI recently. Here's some notes from moving a grub void linux installation onto a new motherboard:

efibootmgr -v

The boot entries you see in efibootmgr are stored in your motherboard's NVRAM (Non-Volatile RAM). Each entry contains a path to an EFI executable (.efi file) on a specific disk partition. These executables are bootloaders that know how to start your operating system.

# First mount your EFI partition if not already mounted
mount /dev/nvme0n1p1 /mnt/boot/efi

# Create new boot entry
efibootmgr --create --disk /dev/nvme0n1 --part 1 --loader /EFI/void_grub/grubx64.efi --label void_grub

you can also remove stale entries:

efibootmgr -b 0000 -B # Deletes Boot0000

and change orders of entries:

# After creating new entry, note its number (e.g. if it's Boot0007)
efibootmgr -o 0007,0004,0005,0006,0002,0000,0003