[iPhone] How to Upgrade Your iPhone 4, 3GS Without Updating the Baseband (Windows)

These are instructions on how to upgrade your iPhone 4 or iPhone 3GS firmware without updating the baseband.

Step One
Create a folder on your desktop called Pwnage

Download the latest version of RedSn0w from here and place it in the Pwnage folder. Likewise, download the firmware you would like to upgrade to from here and place it in the Pwnage folder.

Extract the RedSn0w zip file to the Pwnage folder.