arch-chroot /mnt pacman -S grub-bios
error:failed to initialize alpm library
(database is incorrect version: /var/lib/pacman/)
error: try running pacman-db-upgrade
pacman-db-upgrade
pacman-key --init
pacman-key --populate msys2
pacman-key --refresh-keys
==>ERROR: The keying file /usr/share/pacman/keyrings/msys2.gpg does not exist
==>ERROR: A specified local key could not be upgrade from keyserver
pacman-db-upgrade
pacman-key --init
pacman-key --populate archlinux