SambalBjj,
I think SDH has a good idea to try a PS/2 keyboard and mouse to eliminate USB considerations. And, moreso if the Razer K/B and/or mouse require any special drivers. I use a multimedia keyboard with all kinds of controls and programable buttons for apps, but when fussing with setup, I use a very simple Dell keyboard and mouse from 2010 that must have a completely generic basic driver. If I didn't have luck with that, I would've tried the PS/2 K/B an mouse form the 1007 server. The driver issue is an interruption in everything incvolving hardware changes. Only today while installing a new HD (HGST 4TB) on startup I noticed it was loading a driver while Windows update was configuring something. There was no problem, but I would rather not have that kind of simultaneous disk processes.
These ideas may be a bit extreme, but if you continue to have problems, consider:
1. If the z820 has two CPU's, consider running on one CPU and one RAM module in the first slot.
2. When I recovered the z620 on the firsd try, I used a Xeon E5-1607 V2 (cost $11) which is non-hyperthreading and,
3. Also, I used a fanless 512MB GPU (GeForce 7300 LE) to further simplify the conditions.
4.Last but not least: You may be having the same problem in trying to revert the BIOS to a pre Spectre /Meltdown version.There is microcode in v 3.92 and possibly after that does not allow reversion. When I was trying to revert th veriosn, it would save the 3.92 BIOS, and load the new 3.91 one, but then fail at the very end. Eventually, I learned of the "Magic Green Jumper" that in some way unexplained allowed the reversion from v 3.92 to 3.91. See:
There is apprently yet another level of this, the "Mysterious Black Junper" next to the main MB connector. I didn't use it as the green jumper worked. If you need the "MBJ", I will try and make sense of my notes.
Let us know what happens. I fussed with the BIOS problem for more than two months, until SDH mentioned the crisis jumper and I learned of the Magic Green Jumper.
It seems more than a coincidence that at the time I loaded 3.92 over 3.91, it was also a very newly released version. That 3.92 could not be reverted was not mentioned.
BambiBoomZ