[caf]

Since when do you make a copy of those parts of the chip to use them?

Copyright is about the right to restrict copying - the clue is in the name. The software case is fundamentally different, because your computer must make a (temporary) copy of the software in order to use it.

[jerf]

You don't make a copy, you have a copy. The DMCA applies to such works as well, at least as far as the law is concerned. This is part of why the DMCA is so offensive, the "anticircumvention" clause grotesquely expanded copyright law well beyond the act of mere copying. The act of circumvention becomes illegal, regardless of whether it even involves you "making a copy" in the eyes of the law. The act of playing a DVD on Linux by hacking past the encryption is illegal, even though that is not usually considered "making a copy" in the eyes of the law. (That's also something that has been fought over but I'm not convinced has been settled.)

[caf]

The DMCA bans circumventing effective technological measures intended to prevent copying. The technological measure you'd be circumventing here is one intended to prevent you from using a feature of the hardware, not prevent you from copying a copyrighted work. The DMCA does not appear to apply.

(On the other hand, if they designed it such that you needed to upload a piece of (copyrighted) microcode to the CPU on each boot, then that could well bring it within the remit of copyright law. In that case, if you wanted to produce a third-party version, you'd have to write your own "clean room" version of the necessary microcode, which seems like a pretty high hurdle).