Error running initrd-shell.sh on boot

I've used systemd-tool for a while now. I updated my system a few days ago and rebooted. Now it will not unlock over the network anymore. I get the error on boot:

/usr/lib/mkinitcpio-systemd-tool/initrd-shell.sh: line 141: tty: not found

Entering the password on the machine itself is still possible.