build() {
    SCRIPT="archiso_shutdown"
    add_binary /lib/initcpio/archiso_shutdown /shutdown
}

help () {
    cat <<HELPEOF
This hook will create a shutdown initramfs in /run/initramfs
that we can pivot to on shutdown in order to unmount / and
and others mount points, dm-snapshot devices and loopback devices.
Mostly usefull for dm-snapshot persistent.
HELPEOF
}