You know I used to think that also but I have had to flash a bunch of BIOS the last few years and people have told me just before the computer would no longer boot they had a virus warning.
I have done searches and read up on it and it seems iffy it could happen from a virus.
Flashing a BIOS requires a “flasher” tied to the specific BIOS. It’s not easy for a virus to know that info. It would have to transmit back and receive the proper flasher.