Step 0:
Update to original iPhone 4.0 firmware via iTunes.
• Download PwnageTool 4.01 for Mac OS X
• Also Download Firmware 4.0 (Yes, OS 4.0) and save it to your desktop.
3GS Users: - DOWNLOAD iPhone 4.0 firmware
Depending on your PC the above IPSW File may not save as an ipsw file, it may save as a ZIP file, if it does you will need to change the file type so that snowbreeze can locate it.
Make sure that you safe the above file in a place on your PC that it will be easy to find it and then watch the video below as this is the easiest way for me to show you how to change the file type:
FOR WINDOWS XP:
http://www.youtube.com/watch?v=sQFm0Hi35pc
FOR WINDOWS 7 AND VISTA:
http://www.youtube.com/watch?v=9deovT0nrD4
Step 2: Now start iTunes and sync your iPhone with your PC so that it backs-up all your important data including settings, apps, music, contacts and photos.
Step 3: Download PwnageTool 4.01 and the original iPhone OS 4.0 for your version of iPhone (download links given below). Move all these files to yourdesktop.
Step 4: Start PwnageTool 4.01 and select your device:
Step 5: PwnageTool 4.01 will now automatically detect the correct firmware for your device as shown in the screenshot below:
Step 6: Click on "No" when PwnageTool asks you “Do you have an iPhone contract that would activate normally through iTunes?”:
Clicking on “Yes” will update your baseband to the latest version which will make your device almost impossible to unlock. Do not click on yes, click no
Step 7: PwnageTool will now create the custom .ipsw file for your iPhone which will be jailbroken.
The following “ihaz Success” screen will confirm that the requested .ipsw file has been created successfully.
Step 8: Once the .ipsw file has been created, you will now have to restoreyour iPhone to this custom firmware 4.0 that you just cooked using PwnageTool 4.01 for your iPhone. Click on your phone icon from the sidebar in iTunes. Now press and hold left “alt” button (“Shift” button on Windows) on the keyboard and then click on “Restore” (Not “Update” or “Check for Update”) button in the iTunes and then release the “Shift” button.
This will make iTunes prompt you to select the location for your downloaded custom firmware 4.0 Select that custom .ipsw file and click on “Open”.
Step 9: Now sit back and enjoy as iTunes does the rest for you. This will involve a series of automated steps. Be patient at this stage and don’t do anything silly. Just wait while iTunes installs the new firmware 3.1.3 on your iPhone. Your iPhone screen at this point will be showing a progress bar indicating installation progress. After the installation is done, iPhone will restart automatically and you should now have a fully jailbroken iPhone/iPod touch running on firmware 3.1.3.
