Jailbreak and unlock 3G on 4.0

[wannaunlocknow]

PLease help, unlock not working

I have an iphone 3g update to 4.0 and has a baseband of 5.13.04. I JB with redsn0w and went great. then got to the unlocking with ultrasn0w part seemed to be going great then when my phone rebooted, it says no sim card installed but there is one in there! I have tried reloading ultrasn0w, re-unlocking the phone, 3G was turned off, tried messing with the airplane mode, still no avail Please help, I am going nuts lol...



Well, I turned it off a moment ago and when it came back on it recognized the sim, but only for a few moments ugh!!!!!

 

[Anijake]

Someone I know is giving me a 3G to unlock forthem. I am used to doing it on my 2G via Pwnage tool and just making a custom firmware.

This is what I would like to do for them as well, just make a custom firmware via Pwnage and give them that firmware on a CD as a backup if needed. Can I still do it this way on a 3G? Can I make a custom firmware that also unlocks using the latest Pwnage on a 3G? I plan on using 3.1.2 or 3.1.3 and not 4.0

Thanks