How to upgrade 3g from 3.1.2 to 4.0.1

[i.Annie]

You would use the iPad baseband for your iPhone...

Note that it is a permanent baseband upgrade that is unlockable but Apple can see it if you ever need to take it to them. They will refuse service (unless you get a nice rep who doesn't care). Otherwise, using the iPad baseband is how you would get to unlock.

[VeganBeauty]

Ok. I'll give it a try. Thank you.

It worked!!!!!

[stefan_mkd]

I don't want to open another thread sice i have the same problem. I want to upgrade form 3.1.3 to 4.1. What to do? I clicked save shsh in tiny umbrela and have saved shsh for 4.2.1 only! What to do?

[iYeow]

Here : iClarified - iPhone - How to Jailbreak and Unlock Your iPhone 3G Using PwnageTool (Mac) [4.2.1] to preserve your baseband.

[stefan_mkd]

too bad, since i have windows only. How to do it on windows?

[VeganBeauty]

The steps for a PC are essentially the same, except use RedsnOw. Use the steps below at Dev-Team Blog