well, that risk is exactly why they're testing the idea out in low-end markets first - so the people who would break the security for this probably don't even care for this laptop anyways.
They'd probably argue you're circumventing the copyright protections on the portion of the chip you didn't pay to access, just as circumventing DRM for pre-installed DLC for a game would be a DMCA violation. Anybody's guess what the courts would say about that, that is to say, I'm not saying I agree with this argument, just that I think it would be good enough to get someone selling $25 unlocks into court with a decent chance of serious losses.
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.
Did you actually look at the document I linked to? It explicitly listes the kind of works the DMCA applies to. And none of the things listed says "CPU features" or anything that could be interpreted to mean that by any stretch of imagination.
Yup - which is why the unlock will just end up floating around out there for free, and the concept will just fall by the wayside as not market-worthy. Everyone and their dog will buy cheap chips and crank up the volume.
Yeah, don't try this in the USA. Fortunately it's just software, so you can sell it from anywhere as long as the USA doesn't block your advertising or payment processing.