I just got a replacement from the Apple store for my iPhone 3GS. It is the MB715LL model and has the firmware 3.1.3. The modem version is 05.12.01 Now, I attempted to jailbreak ( NOT unlock) the phone by using snowbreeze. After I generated the cracked firmware, I tried restoring using iTunes with it, but got the error 1600. Then, I tried using Redsnow with the 3.1.2 firmware and all, and the program got stuck at the "waiting for restart" sequence, with my phone's screen not on. I am now completely clueless as to how I can jailbreak my phone now. Any ideas?