Right, the main 'technical reason' is that nobody has figured out how to
correctly unencrypt the Apple firmware, and until that can be achieved a) we
can't find out how to control the hardware in these devices, since that
requires being able to reverse-engineer the original code and b) we can't
figure out how to replace the Apple firmware with our own, since that requires
being able to encrypt ours in the same way Apple use in order for the ipod to
recognise it as valid software. Same goes for ipod Classic
