hi, i have an iphone 3g was working fine on 3.1 not unlocked and not jailbroken. I tried to jailbreak it using cosutme firmware it gave me error 1604 so i downgraded the phone to 3.0 then jailbroke it with redsnow then again used custom fw 3.1.2 to restore as 3.0 was not giving no service but after restoring with custom fw still no service wt can be wrong thanks