Updating cpu microcode Xxx broadcast chat
These microcode updates are normally bundled in with BIOS updates.Given the fact that BIOS updates are inherently risky, motherboard manufacturers are reluctant to issue BIOS updates for anything other than major bugs. Both Intel and AMD realise this and release standalone microcode updates.
Would a person with no access to special processor documentation be able to change the CPU's microcode in order to obfuscate the machine's instruction set?
You're very much getting into the realm of "Here be dragons" when you look into hardware manipulation like this.
I don't know of any research or in-the-wild attack that has done any practical experimentation with this, so my answer will be purely academic.
The brain or engine of the PC is the processor (sometimes called microprocessor), or central processing unit (CPU).
The CPU performs the system's calculating and processing.
In that case though, the clone had become more popular than the original.