I'm pretty sure iOS updates are signed per device, as that's why everyone backs up their signatures for old versions (so that they can go back while Apple isn't

I'm pretty sure iOS updates are signed per device, as that's why everyone backs up their signatures for old versions (so that they can go back while Apple isn't signing them). So Apple could only sign this backdoor for one device. http://www.saurik.com/id/12 http://www.saurik.com/id/12