If you already downloaded PwnageTool 3.1.5 then you may be wondering how you going to use that tool to jailbreak your updated iPhone OS 3.1.3. Remember a wrong step may make your iPhone useless, so use the following steps carefully. You must note, the following instruction are educational purpose only and we are not responsible for any loss of important data or malfunctioning of your iPhone.

Required Tools

1. Download iTunes 9.0.3

2. Download Original iPhone 3.1.3 Firmware

3. Download PwnageTool 3.1.5

Instruction For Jailbreak iPhone OS 3.1.3 with PwnageTool 3.1.5

Step 1: 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 2: Start PwnageTool 3.1.5 and select your device.

Step 3: PwnageTool 3.1.5 will now automatically detect the correct firmware for your device.

Step 4: Click on “No” when PwnageTool asks you “Do you have an iPhone contract that would activate normally through iTunes?”.

Step 5: PwnageTool will now create the custom .ipsw file for your iPhone which will be jailbroken.

Step 6: Once the .ipsw file has been created, you will now have to restore your iPhone to this custom firmware 3.1.3. Click on your phone icon from the sidebar in iTunes. Now press and hold left “Alt” button on the keyboard and then click on “Restore” and then release the “Alt” button.

Select that custom .ipsw file when prompt by iTunes and click on “Open”.

Step 7: Now wait for iTunes to complete iPhone 3.1.3 restoration. After successfully completing installation your iPhone will restart automatically. If you followed the instructed steps properly then you now have a jailbroken iPhone with 3.1.3 OS. You can now restore all your settings, apps, music, contacts and photos to the newly installed firmware version 3.1.3 by restoring the backup that you made in Step 1 from iTunes.

Source: Redmondpie