Lenovo TS P320 UEFI/AptioV - Serial Console Redirection only working with graphics ca

[c0d3z3r0]

Hi all,

I am trying to debug and fix a very annoying bug in UEFI (AMI Aptio V) of my ThinkStation P320.
Since the machine is going to be headless I removed the graphics card which saves me 13W in idle.
By modifying the Setup NVAR I was able to enable Serial Console Port Redirection.

With graphics card inserted I see the POST screen on serial console and can react to errors like "Checksum error. F1 to enter setup, F2 to resume."
(There is no need for attaching a monitor. The card just has to be inserted.)
   

Without graphics card I only get some of the output via Serial and the system does not react to F1/F2/<whatever>.
Looks like everything from the modules PostScreenInfo and ErrorMessage is missing.
   

Without graphics card, when there is no error, I am even able to enter setup.
   


Is there anyone with an idea about what is wrong here and how I can solve that?

Best regards
Michael

[c0d3z3r0]

Update: When I remove the ErrorMessage module at least I don't get a blocking error that I cannot respond to... so the problem must be related to that module anyhow...