Hi nrickert,
I had gathered that and found some more references to legacy deep in BIOS. Disabled what I found and have broken it. Now no access to the machine whatsoever. Looks like I have broken it completely. I have no idea how to access BIOS now, no screen and strangely no ethernet although this was not disabled.
The only data that might not be backed up is on NVME. I have an identical machine still running. Can I put that in a spare slot and would my spare machine be able to access the data?
I suspect not but would appreciate suggestions.