> Basically if someone has physical access to device, its game over.

It took more than a decade to exploit this vulnerability and even then there are fairly trivial countermeasures that could have been used to prevent it (and that are implemented in other platforms.)

Nothing is unhackable, but it requires a very peculiar definition of "game over".

(And as others have pointed out: only early versions of this Xbos One where vulnerable to this attack.)