Client boot issue with Debian Edu v12

Hi folks,

I did a new installation this morning.

I'm trying to boot one client laptop using PXE, which fails. This used to work just fine in previous test installations I did a few months ago. I'm not 100% sure but I think it was entry "Diskless Workstation (64-Bit, server's SqashFS image)".

I'm getting the following output:

[...]
Begin: Running/scripts/init-bottom mount: mounting /dev on /root/deu failed: No such file or directory
mount: mounting/deu on /root/deu failed: No such file or directory
mount: mounting /run on /root/run failed: No such file or directory
done.
run-init: can't execute '/sbin/init': No such file or directory
Target filesystem doesn't have requested /sbin/init.
run-init: can't execute '/sbin/init': No such file or directory
run-init: can't execute '/etc/init': No such file or directory
run-init: can't execute '/bin/init': No such file or directory
run-init: can't execute '/bin/sh': No such file or directory
run-init: can't execute'': No such file or directory No init found. Try passing init bootarg.

BusyBox v1.35.0 (Debian 1:1.35.0-4+b3) built-in shell (ash) Enter 'help' for a list of built-in commands.

(initramfs)

Any ideas, how to fix this?

Kind regards,
Roman