I understand that you are experiencing problems to update your BIOS and using a video card on your computer.
In regards to your inquire, I recommend you to try flashing the BIOS to the same version that you have via recovery method and to enable the expansion card text option in BIOS to help the recognition of the video card.
As you can read above, unfortunately even trying to update the BIOS via recovery method fails. I have not found any workable method to be able to update the BIOS as of yet.
I was able to get the machine to post again, however enabling Expansion Card Text did not remedy the issue. I still have lock-up on the BIOS splash screen.