Congrats on the recovery. I have never done that, and it is interesting to know that the newer BIOS version opens up more modern ways to update BIOS. I always update BIOS from within BIOS now.... that may be why I have not had to do the BIOS recovery.
For the current version of BIOS, 2.38, you'll see the USB option if you have a USB drive in place..... always put the single .bin file from the DOS folder that gets placed in the swsetup folder on root c at the top level. You can make the .bin extension visible by going into Folder Options and setting the pref to show extensions for known file type.
That 922 is, in fact, the fatal error on FSB that you get when the motherboard cannot run the E5345 quad core. I always have dropped back to two of the E5160 (latest stepping) in that case. The performance is a bit less than two of those E5345s, but if you want to keep cost down I'd do that. You get more cores with the 2 quads, but each of those runs slower. You get less cores with the 2 dual cores, but each core runs faster. So, what I've evolved to is that if I can run two quads I will, but if not then I'll stick with 2 of the E5160 and not throw away the motherboard. If you can run 1 you can run 2 is the rule for both (and you should always run 2).
SSD.... get the SATA gen II Intel 320 series 300GB (or 160GB). You really should be using a SSD, and you can get the 300GB size for about $100.00 now off eBay new. Or, a used 160GB one for about $40.00. Download the latest Intel Toolbox utility, 3.3.3, if you get one of those.
There is BIOS cloning..... it is termed "Replicated Setup" by HP. If you pm me via this forum with your email I can send you my tuned up copy for the xw6400 for fastest boot and highest performance. You can capture yours and save it, and experiment with mine, and go back and forth. Same idea as with updating bios from within bios..... you simply put that little .txt file on the top level of the USB thumb drive, cold boot and F10 into BIOS, go to replicated setup, choose to load from the USB and hit go. It is virtually instant.
Latest drivers..... turns out you can get universal installers from later HP workstations for such things as Broadcom and Realtex, and run those and use those later drivers just fine on the 6400..... been doing that for years.
It is great that you were able to recover your BIOS. I too have not been able to figure out exactly what that Crisis Recovery jumper does, but maybe Dan in WGBU (very helpful HP engineer on this forum) will see this and let us know.