Old 3GS 3.1.2 to 4.1 jailbreak/unlock

[D.Schrute]

I need to upgrade my 3GS to 4.1 for the multitasking and folder features. I'm on baseband 05.11.07 which I want to preserve to get the unlock. Also the 3GS is on the old bootrom and I'm on windows xp. I don't want to go up to 4.2.1 because I don't wanna lose the gps.
Please let me know how I would go about doing this.
Thanks.

[reVain]

[ame=http://www.youtube.com/watch?v=QFAY0A4mtPk]YouTube - How To Jailbreak & Unlock iPhone 4/3Gs/3G 4.2.1 With Baseband Preserving Sn0wbreeze/Pwnagetool Tools[/ame]

That should help.

[D.Schrute]

would this affect the GPS?

[reVain]

Not that I am aware of. That error only comes from changing your iPhone 3GS baseband to the iPad 06.15.00 baseband.

[i.Annie]

You'll need SHSHs to go to 4.1 or 4.2.1. Be sure you have that.