Hi everyone , I have Iphone , I am trying to update custom firmware but always get 1600 error, I have tried everything , but nothing helps. When I try to update offical 4.2.1 firmware in iTunes - error 1015. But it is possible to update offical firmware through the redsnow (Select IPSW). Everything is ok than. Also there is possible to update 3.1.3 custom firmwares such as whitedoor ,blakdoor and so on. But when I try to update 4.2.1 custom firmware I always get 1600 error. Of course device is pwned dfu, I have comment row in host file ,but nothing helps. I want to update custom 4.2.1 firmware . Hope, you can help me to solve this problem. Thx in advance. P.S phone is locked .