HP Z2 SFF G9 - Trying to fix BIOS after “critical failure" > No Recovery

Heya,

I’m currently trying to fix a “HP Z2 Small Form Factor G9 Workstation (5F0D1EA)” after HP issued a warning that some models may become entirely unbootable if left on specific old versions. The exact issue happened to the one I got right now: https://support.hp.com/us-en/document/is...8577455-16
Due to this bug the BIOS is so broken that no recovery option works anymore...  It simply turns off 2-3 seconds after being turned on.

I’ve already desoldered and dumped the broken BIOS, however another person took a look at it and said the dump is apparently not fixable… I guess the current one truly is fully dead, I bet HP forgot to limit something in those older versions and over time overwrites other critical areas… but not sure. I’m a beginner so not even sure where to start looking but willing to learn 

Board Details:
SCRABBLE
REV: A
M11 FMB-2202
Model Nr.: 5F0D1EA#ABD
Ser. Nr.: Please DM if needed, thanks!

Link to the latest BIOS for this model: https://ftp.hp.com/pub/softpaq/sp158001-...158267.exe


Thanks a lot already for any kind of help