no need custom firmware How Unlock Without Wifi etc.
just restore with original 3.1.2 Fimrware version after complete restore
keep attach Cable in Iphone run
BlackRa1n.exe just wait few Seconds after that you'll see now your phone jailbreak
just run Install.bat (under without wifi folder) now reboot your Iphone
Your Phone Unlocked Without Wifi ;-)
Happy Unlocking