It's not all BIOS updates either, in my experience. Only those that affect parts of the firmware inside the CPU since the BIOS itself is way to late in the proc

It's not all BIOS updates either, in my experience. Only those that affect parts of the firmware inside the CPU since the BIOS itself is way to late in the process. (ie Microcode updates, IME/AGESA/PM updates, etc.) Personal experience confirms this somewhat, as boot after BIOS update can take 15 seconds or 1 second, depending on the update.