Unlocking a previous unlocked iPhone

[djs5150]

Okay, I apologize in advance if this question has been answered for the 19343297th time, however I couldn't find it. I have an iPhone 3g that is already jail broken and unlocked to use with T-Mobile. However, I need to update from 2.2.1 to 3.1.2 but I don't know the right steps to proceed. Do I update my phone through iTunes first, or is there something else I need to do? I'm totally new to all this and read one of the guides above but it only pertained to 3.0 fw. Also worth noting, there is a chip in my phone that I'm told I don't even need if I unlock my phone the "correct" way. Help?

[GIRLLLLLLLLLLLLLLLLL]

If you update, you will break the Jailbreak & unlock so you shouldn't bother. You have a couple of options, restoring with a custom jailbroken firmware provided from Pwnagetool and unlocking with ultrasn0w, or restoring to the official 3.1.2 and using Blackra1n/Blacksn0w to jailbreak and unlock. I would use pwnagetool, and if you don't have a mac, PM me.