A modern motherboard can update it's BIOS from a USB stick WITHOUT a CPU or memory installed.
Think about that. The motherboard "knows" how to read a FAT file system from a USB mass storage device, verify it's digital signature and flash it with no main CPU or memory.
Think about that. The motherboard "knows" how to read a FAT file system from a USB mass storage device, verify it's digital signature and flash it with no main CPU or memory.