Installation

pacman -S grub efibootmgr
grub-install --target=x86_64-efi --efi-directory=/efi --bootloader-id=GRUB

user configuration file

• path: /etc/default/grub
• default kernel

#  When you manually choose a different entry, that becomes the new default.
GRUB_SAVEDEFAULT=true
GRUB_DEFAULT=saved

Generate the main configuration file

grub-mkconfig -o /boot/grub/grub.cfg