if ! [ -d "$cmdpath" ]; then
    # On some firmware, GRUB has a wrong cmdpath when booted from an optical disc.
    # https://gitlab.archlinux.org/archlinux/archiso/-/issues/183
    if regexp --set=1:isodevice '^(\([^)]+\))\/?[Ee][Ff][Ii]\/[Bb][Oo][Oo][Tt]\/?$' "$cmdpath"; then
        cmdpath="${isodevice}/EFI/BOOT"
    fi
fi
configfile "${cmdpath}/grub.cfg"