[shakna]

I remember trying to prove that this was impossible... Until I killed a floppy reader.

But now? When microcode can be patched? I'm waiting for tamperproof ransomware, that holds your hardware as well as your data as the hostage.

[duskwuff]

CPU microcode is volatile, for what it's worth. Patching it only lasts until the machine is powered off.

Firmware in other platform devices, however, may be vulnerable to modification -- BIOS, network adapter, video card, hard disk...