I tried to update my iphone 3g 3.1.3 with PwnageTool 4.1.3 custom firmware file and I ended up with 1604 error and connect to itunes symbol. What can I do to either restore to 3.1.3 or to update to newest firmware but without updating the baseband?
Which baseband are you on? or were you on before you started the process? Just remake another ipsw with pwnage tool and try to restore to it again. When you connect the iPhone does iTunes detect it? You can try putting it into DFU mode and restoring to the ipsw but I'd just make a whole new one.