iPhone upgrading from 3.12 to 4.01 help

Itunes has stopped signing 4.01. The only ways you can do it are to use "tiny umbrella" to "fool" itunes or do a google for snowbreeze.. its just been updated to allow the jailbreak of 4.02
if u have ur shs blobs saved on cydia add: gs.apple.com

to your hosts file : (C:\WINDOWS\system32\drivers\etc\hosts ) btw hosts is the file it has no extentions

it will sign ur fw using cydia server ..

have downloaded new firmware from here
iClarified - iPhone - Where To Download iPhone Firmware Files From
the 3gs 4.01
tried to restore via i tunes using shift clik restore method
says is incompatible

any 1 help

just wanna upgrade the mrs phone to 4 os it has already been jb using blackrain

Make sure you have downgraded the right FW for the phone, and not the 2g or 3g versions. I had this problem with mine, and found out I had downloaded the wrong version. lol