Ok so a friend of mine wants to unjailbreak his phone cause he wants to be able to update to IOS5. I tried to jailbreak my phone earlier, but I think the problem with what I did was that I restored and updated. Thus after everything was done, it came up with a screen that said plug into iTunes and once I did iTunes told me it couldn't read my SIM card for some reason which is wrong because I have a legit SIM from AT&t. So I had to go to the apple store and thankfully they just straight up gave me a new iphone 4 which was just awesome. So can anyone help us unjailbreak his phone that is running 4.2.1, without updating to 4.3.3. He just wants his phone back to normal! Please help!