Update to what? Do you need the phone unlock?
update to the latest version and it is already unlocked sorry my english is ok
importantly, you must not update via iTunes, that will prevent you from unlocking.
You can use PwnageTool to upgrade to 4.2.1 (if you have a mac) while retaining your baseband to unlock. Or you can download a custom 3g 4.2.1 ipsw from a website that you can trust.
Hi PsstGreek,
I heard that you can only stop up to 3.1.3 on an iphone 3g. is that true?
You can go to the newest iOS on a 3G. An iPhone 2G stops at 3.1.3
People have said when they've upgraded their 3G to 4.0 or higher that it has slowed down their iPhone a lot. That's what you must have heard.
With a 3G i'd stick with 3.1.3
Anything higher than that and it will be slower than a turtle.