I got a 3gs which was running 4.5.3 with 05.16.02 firware, I need it unlocked. So I downgraded it to 4.1 stock apple firmware, now I am stuck in the recovery mode loop. iPhone keeps coming up to connect to itunes screen. I have tried tiny umbrella exit recovery option, no luck. I have tried tiny umbrella fix recovery option, no luck. I have tried the whole iRecovery -s command, which connects to my iphone and after typing several commands in it reboots but keeps coming back to the recovery screen. I have tried restoring again to stock 4.1 ipsw but keep getting 1604 error. What should I do?