Look at the patch in #15, works fine.

Rolf

My encrypted partitions are working but I have a problem when shutting down the system: The console blocks and displays the message

Stopping remaining crypt disks...sda2_crypt(busy)

several times. After about one minute it displays an error message

stopping early crypto disks failed.

and the system is shut down.

The wgquick@.service unit file uses the .ini style ('cos the devs love Windows, presumably) and so cannot be used with sysvinit, you will need to convert it to a shell script instead.

Something like this executable file in /etc/init.d/wireguard might work:

#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          wireguard
# Required-Start:    mountkernfs $local_fs
# Required-Stop:     $local_fs
# Default-Start:     S
# Default-Stop:      0 6
# Short-Description: WireGuard via wg-quick(8)  
### END INIT INFO

. /lib/init/vars.sh
. /lib/lsb/init-functions

do_start() {
   /usr/bin/wg-quick up mullvad-se4
}
do_stop() {
   /usr/bin/wg-quick down mullvad-se4
}

case $1 in
(start|restart|reload|force-reload)
   do_invoke start
   ;;
(stop)
   do_invoke stop
   ;;
(*)
   echo >&2 "Usage: $0 {start|stop|restart|reload|force-reload}"
   exit 3
   ;;
esac

Enable it with

# update-rc.d wireguard defaults

Disclaimer: I'm crap with sysvinit scripts so perhaps wait for somebody to point out my mistakes before trying this.