Comment by tuetuopay

> I don't know jack about hardware but it would seem obvious that when one designs a chip, you make sure it does not have 'unknown hardware registers' or unknown anything when you get it back from the manufacture.

well you are in trouble then. all of modern hardware have such hidden parts in them, and are most of the time referenced as "undocumented" instead of "unknown". I know this seems pedantic, but from a public eye, anything undocumented is unknown. what makes those special however, is those are not used at all by public software, thus truly unknown as one can only guess their use or even their mere existence.