I fixed it.
Found the flashing port pinout on a forum thread, posted by elmor on the rog forum.
Trimmed out the first 4 kilobytes of the bios on the website and got the true rom file. Flashed it using a lot of cable clamps. On my old Z97-AR it would've been much easier, just pull out the chip as it was socketed.
Original serial number has been lost, could probably restore it with afuefi but I frankly don't care. Ethernet mac address is not stored with the chip unlike on intel platforms, so I didn't lose the mac address.
Overall a pretty simple fix if you have the proper information, which ASUS won't give you given their systemic "user is an idiot" policy.
Last edited by p4block; 01-30-2020 at 01:42 PM.