iPhone upgrade question

[twizotte]

I have an iPhone 3GS, 3.1.3. I need to upgrade it to 4.0 or over. But still need to maintain minimally a jailbreak.

Is this possible? I've checked around. I've saved my SSH blobs but I believe that will only allow me back to 3.1.3.

Ideas? I believe I am on the new bootrom. 5.12.01 Firmware.

 

[Corndog5595]

http://www.felixbruns.de/iPod/firmware/

Download the 4.0.1 firmware for your device and then hold down shift and press the restore button in iTunes. If you are on a mac, hold down the Option key and then press the Restore button.