[Request] HP z220 add headless mode /no GPU installed/

Hello,

I am trying to run a HP z220 headless… tried everything that I could find on the internet >> updating BIOS, using the replicated setup with the “Headless Mode” enabled, but I can’t get the thing to pass POST without the GPU inserted…
Is this a hassle to mod? Can somebody help?

Attaching the latest BIOS from HP.

Thanks!