Update
So I was messing with some IFR variables, I managed to brick the bios.
Recovery was interesting, I made a FAT (not fat32) drive with the 2.5.1 exe, the 2.1.0 bios exe renamed BIOS_IMG.rcv as well as the setup rom file from 2.2.1.
following the standard procedure, unplug batt- cmos batt- hold power to clear nvram- replug - plug in usb then hold escape/ctrl and plug AC did not work.
However on second attempt I placed placed the flash drive in (left plug) BEFORE reconnecting the battery (i connected rtc battery first followed by main battery)
As soon as the battery connector went in it booted right up to an error about defaulting BIOS. (no keys pressed or held, no AC plugged in)
I attempted to flash bios from the F12 boot menu, however it did not work with the slightly unbricked bios.
Then I powered off, held escape/control, plugged in power cable (with usb in left slot) and loaded the BIOS recovery mode.
This allowed me to downgrade all the way back to the factory shipped 2.1.0 from 2.5.1
One tidbit which may or may not mattered was the battery connector only went in about half way the second time, so when it finally booted the front LED was flashing orange/white, and the laptop did not recognize the battery (even though it booted without power plug) so it refused to do a BIOS recovery, I shut down pushed the battery connector in the rest of the way and rebooted into BIOS recovery.
Perhaps the battery giving power but not info was what jogged it to boot. Regardless it took a good hour of mucking about to get it to boot.
To be clear I had 3 bios revisions on the recovery drive, stock 2.5.1.exe, the 2.1.0 exe renamed BIOS_IMG.rcv and the 2.2.1 ROM file. BIOS recovery console did not let me select a file, it chose 2.1.0 which means the proper fix must entail having the BIOS executable renamed to BIOS_IMG.rcv for the ctrl/esc recovery to work. It may also allow others to downgrade.
Im now going to update to 2.2.1 (same bios as my other device I dont want to brick) and start playing with IFR again.
Any input would be appreciated