So, i bought an iPhone 4 from a guy on ebay, but it is still a locked iphone. I accidentally upgraded it to 4.3.5 so my baseband turned to 04.11.01, which is not unlockable by ultrasn0w. But, my friend was able to jailbreak it in a way, where it is kind of jailbroken, but i do not have cydia, but I am able to just put in my ATT GoPhone Sim card, and it works. Do all Att SIM cards just work if you put it in an iphone 4? Could I upgrade my phone onto ios 5, from itunes and just put in my sim card and works? Thanks.