Hi I have an iPhone 4 16 gb for at&t I really want to use it for tmobile Many told me it's impossible to jailbreak and unlock it But I jailbroke it and have Cydia installed on it. (i think it's tethered ? every time i reboot it i have to plug it into computer and go into DFU mode with redsn0w in order to use Cydia) Anyway I'm trying to unlock it and I've tried almost everything. I have tried downgrading bb and iOS but it's not working I don't have any SHSH blobs and I don't know how to get them. Someone please help me!!!