Hey everyone, i have an iphone 4 jailbroken with version 4.1 with modem firmware 02.10.04. i want to upgrade to ios 5.1.1 while keeping the firmware the same so it remains unlocked. i used sn0wbreeze and redsn0w and even iREB, but after getting into pwned DFU mode, and opening itunes and shift+restore and clicking the custom ipsw, itunes tells me an error 1601 or 1602 has occured. can someone help me with this? any help is appreciated. thanks