My apologies if you have already answered this but how did you run the BIOS updates ?
After copying all the bioses to a pendrive each in a folder of their own, 1) rebooted, 2) went into bios, 3) loaded optimized defaults, 4) rebooted, 5) flashed with q-flash (setting "keep dmi data" enabled or disabled didn't change the results), 6) rebooted, 7) loaded optimized defaults,
rebooted. All bioses from F6 to F10 work perfectly. F11, F12 and F13b bioses make the pc run into a reboot loop past the POST screen.
Then followed the unplug power cable and remove battery (for 10min) suggestions, and started over. Needless to say, I'm still stuck with the F10 bios.