grub-install --target=x86_64-efi --efi-directory=esp --bootloader-id=grub

Installing for x86_64-efi platform.
grub-install: error: esp doesn't look like an EFI partition.
.

mkfs.fat -F32 dev/sda3 (the efi partition)
mount /dev/sda5 /mnt (the linux filesystem)
mount /dev/sda3 /boot (to mount the efi partition in /boot as reccomended)