HELP! I know how to unlock and jailbreak iPhones (I've done it for friends by watching YouTube videos to learn how) but I don't know much about how the whole update thing works. I bought my first iPhone yesterday to be used on T-Mobile. It is a used iPhone 3G that is currently running the 3.0 software. I went to plug it in to the computer to restore the phone and update it to 3.1.2 but realized that there was the 3.1.3 update available. So, does that mean there is no way to update to 3.1.2 because 3.1.3 is now available? It looks as if that's what you are all saying in the post above, but I'm not much of a tech person so I didn't understand some of the lingo and shorthand used above. I have to have the phone unlocked since it is for T-Mobile, which I can do since it is 3.0 but I would rather have 3.1.2 just so I can have some of the apps I downloaded.
You should do the following:
1) Do not restore.
2) Jailbreak at 3.0 using redsn0w 0.8
3) Create or obtain a hacktivated custom 3.1.2 firmware (these are created using PwnageTool -- do not use the stock 3.1.2 firmware from Apple).
4) Shift-restore or command-restore to this custom 3.1.2 firmware.
This will preserve your phone's baseband at 04.26.08 and allow you to unlock using ultrasn0w. Be sure never to upgrade to a stock firmware. You will always want to wait until the new version of PwnageTool is created before upgrading.