It's hard to change the behavior of the CPU because it's in the middle of the chip and highly speed-optimized. It's much easier to add an extra chunk of silicon

It's hard to change the behavior of the CPU because it's in the middle of the chip and highly speed-optimized. It's much easier to add an extra chunk of silicon that affects one of the peripherals. I'd probably add something in the southbridge to spoof the BIOS flash.