Having an issue here

[S00nerfan]

Okay so I have an iPhone 3G with a Modem Firmware of 5.12.01 and it's running the 3.1.3 OS. For some strange reason, this iPhone will not join a wifi connection no matter what. I've tried every single tactic to connect. So, I wanted to unlock this iPhone 3G for another carrier. Now, I know the basics behind this, however, I can't connect to cydia since I don't have wifi. So I'm really not sure how. Is it possible to unlock it for other carriers with 3.1.3 and the 5.12.01 baseband? And if not, is there a way to downgrade it so you can use it for other carriers but downgrade without wifi? Thanks in advance

[davesnothere11]

No sorry but that baseband is currently not able to be unlocked. Also you can't go back to a previous baseband with a firmware downgrade.