Hello, I have iphone 4 with 5.0.1 (9A405), and I would like to upgrade to 6.1.2. I downloaded the official firmware iPhone3,1_6.1.2_10B146_Restore but normal shift+restore in itunes didn't work. I tried in DFU mode, but it didn't work either. I got error 3194, so I tried to edit the host file (added 18.104.22.168 gs.apple.com, restarted my computer, and when that didn't work I added # before that line and restarted, but that didn't work either). I also tried totally removing the host file from that folder temporarily, and disabled my internet connection, but no success either. I downloaded tinyumbrella, activated the server, and this time I bypassed apple's server check, but then I got error 1600! I tried to solve that with iReb, PWNED DFU, but it didn't work (with or without tinyumbrella's server running)... clearly I searched a lot, but that's all I could find. what is the next step to update it to 6.1.2 (it's an unlocked phone, so I don't care about the BB). Thanks!