Futro S740 doesn't boot without monitor

[futro740]

Hi all,

my Futro S740 does not boot properly if no monitor is attached via Displayport.
I am running the latest BIOS and have it configured to continue on errors.
I am running Ubuntu server 22.04 LTS. If I plug in a monitor during boot everything works fine. If I unplug it it stays fine. Until the next reboot.
Any ideas what I can do? I want to run it as a server and thus without a monitor attached to it.