I have an iPhone 4 running iOS 4.2.1. The home button has stopped working and I'm pretty sure its a hardware problem. So I want to take it back to the shop which means un-jailbreaking I tried to do an itunes restore back to 4.2.1 but I got an error "This device isn't eligible for the requested build" In iTunes I can restore and update to iOS 4.3.5 but I've heard you have to be carful when updating jailbroken iPhones because you can get assorts of problems. And I really cant afford to screw it up because if I do I can't even get the phone into DFU mode because the home button doesn't work. So what should i do? Can I just restore and update to 4.3.5 Thanks in advance for your help!