(This is all based from my knowledge which is somewhat limited so it might not be accurate) Similar to the other idea which involves redirecting an app, this one is the same but with the firmware update. The whole idea with the app is nice for putting apple signed apps on your ipod for free without the need of purchasing from itunes. But for editing the ipod like install.app and cyndia do, the only way would be to access the root which apps cannot. Imagine the ipod is like a computer with an admin account but your limited on your account, you therefor cannot edit the important information and the admin account automatically terminates applications and processes which it thinks are not supposed to be there. The admin account is accesses by apple during an update to allow the replacement of core information. Therefor can we not just edit the current firmware to allow whatever it is we want it to allow? Either by downgrading to an older firmware and updating it with an edited current firmware, or editing the current firmware, making it seem to be an update to the old one (make the ipod think its newer then the current one) and have it download our own firmware. Thats my two cents. Remember, im not 100% sure of the situation so once again this is all theory and speculation.