i have an iphone 4 that will not come out of dfu mode. I can jailbreak it with greenpoison and it goes all the way thru but in the end screen goes black and its in dfu mode again. Itunes wont restore it either. 3194 error. It is running 4.2.1 firmware. I have tried restoring with snowbreeze firmware and still nothing. is there a way to get it out of dfu mode?