Originally Posted by jswinden
Anything can be reversed engineered given the time and resources.
If Amazon made no mistakes or bad design decisions when creating the new signed update system then in theory it could be nearly impossible to break in barring any new advances in cryptography or quantum computing. For a product like the Kindle, it just isn't worth the time necessary to audit the code to this level especially since it is a fairly complex device.
That said, Apple and the various phone manufacturers have much more to lose from the ability for people to break into their devices and they've not been successful in preventing that from happening so far...