Advice re: upgrading from 3.1.3

[sumblokecalledpuffy]

Hey, I have a 3GS new bootrom on 3.1.3 jb with spirit and unlocked with ultrasn0w. I realise I cannot upgrade to 4.1 and preserve baseband, but is it possible to upgrade to 4.0.1 and then unlock? I'm afraid to upgrade to 4.0.1 in case it updates the baseband hence leaving me with a useless phone. Any advice would be great, and I have SHSH's for 3.1.3 and 4.0.1. Thanks

[iYeow]

Yes, you can upgrade to 4.0.1 . Do this :
Run Notepad as Admin , open up hosts file and add this line :
74.208.10.249 gs.apple.com
save it and reboots your pc
Now do the Shift + Restore to 4.0.1 ipsw
Once restored , put your official sim card in
Install Jailbreakme 2.0 from Safari on your iphone.
Unlock with Ultrasn0w from Cydia.

[sumblokecalledpuffy]

Thanks for the reply. I'll give it a try

I get unknown error (13) when attempting shift restore to 4.0.1 any suggestions?

[iYeow]

Use kick out of recovery from Tiny umbrella.

Have you updated your itunes to the latest yet ?

[sumblokecalledpuffy]

I'll retry. It's 9.1 is that ok?

[iYeow]

Atleast 9.2, go for the 10 is fine.

[sumblokecalledpuffy]

It's taking a while to download so gonna call it a day for today, will come back to it tomorrow. thanks for your help.

[sumblokecalledpuffy]

Hi, I'm back to try again! I keep getting error 3194 even though tiny umbrella and cydia states I have my SHSH's for 4.0.1

I've edited the hosts file and I'm using itunes 10.

Somebody please help - I'm losing the will to live.

EDIT - I've managed to do it successfully and regained the will to live! Thank you yeow202 for all your help - much appreciated.