I solved the problem myself.
So the Bios was still there, but somehow the dashboard was changed back to default.
I used the AID4.50 bootdisk with defaults that allowed me to copy the EVO-X dashboard to the XBOX and ...
Voila!
It works again.
WHy did it change?
I have no clue, but the problem is solved and I know how to help myself the next time it might happen.
Have a nice time!
