Simply entering the BIOS on a ProDesk 400 G3 will cause it not to boot after exiting

[roakey]

HP ProDesk 400 G3 Desktop Mini PC (1GG00UT)

BIOS P23 Version 2.07 6/14/2017 (updated as directed after purchase)

Windows 10 as it comes with the machine

Looks like a severe BIOS bug:

Since the install of BIOS P23/2.07 if you enter the BIOS (even if you change NOTHING) afterwards it won't boot*. Restore factory defaults, will boot. This simple sequence will cause and recover from the problem:

To cause the problem, starting with a system that will boot:
Power on, F10, enter BIOS
Without changing anything, immediately exit discarding changes
Won't boot (even if you power off and on again)

To recover:
Power on, F10, enter BIOS
Restore factory defaults
Will boot.

I was able to successfully change BIOS settings using the "shipped with" BIOS (2.04) - I had enabled, and was using virtualization. I have VMs on this machine, I just can't use them now due to the fact that I'm being FORCED to factory defaults in order to boot. After install 2.07, I can't change any BIOS settings because the machine won't boot afterwards.

Ps. I just retired from HP after 37 years in diagnostic engineering and firmware development. Please don't dismiss me as someone who simply messed up the BIOS settings. Just ENTERING the BIOS and exiting it WITHOUT CHANGING ANYTHING causes this problem!

*Here's the diagnostic engineer in me coming out: Let me define "won't boot" which contains a debugging data point. I originally thought I messed up the BIOS settings (I changed the video memory to 128Mb, for example). and the machine would not boot. Changed video memory back to its original value and it still wouldn't boot. After restoring to factory defaults it booted and I kept doing simpler and simpler changes to the BIOS - all resulting in the system not booting. Finally exhausing all possibility that it was someting I was doing wrong, so (many hours later) I just entered and exited the BIOS without changing anything - and it didn't boot. It actually goes to the network boot since it can't find a disk or CD to boot (since disk, CD and network are factory defaults). So for some reason it can't find the boot block on the disk after you merely ENTER the BIOS.

Do a factory restore and it works again. Enter the BIOS (F10) and immediately exit and it won't boot again.

[roakey]

According to the BIOS, the previous version was 2.04, but using the BIOS I appear unable to rollback to it due to some policy setting I can't find.

Roger