I apologize for the silly question, I am coming from Android and I'm pretty new on iPhone hacks / jailbreaks. On my HTC Android phone, I used to play with custom roms all the time. On Android, once you are 'rooted', you could do practically anything to your device. HTC would occasionally provide updates to the OS, and devs would hack the updates (adding / removing components from it) and provide custom update packages ready to be flashed to the device. Why isn't such thing done with the iPhone? Is there any technical reason on why no one has ever devised a way to modify the Apple updates, add baked in root access and Cydia, and just flash that on top of an already jailbroken iphone? I am not saying at all this is easy, but I can't help but wonder why it's done all the time on Androids but not on iPhones.