The new iPhone firmware iOS 4.0.2 is finally here and it has been jailbroken already using the existing version of Redsn0w. Here’s the how-to guide on jailbreaking your iPhone 3G or iPod touch 2G (non-MC model) running on iOS 4.0.2 using Redsn0w tool.

• First, you need to download the iOS 4.0.2 firmware for your iPhone or iPod touch.
• Now you need to update the firmware of your device using the IPSW file which you just downloaded. Simply open iTunes and restore to the downloaded firmware, or you can simply click on “update” if you’re experiencing and difficulties.
• Launch Redsn0w 0.9.5b5-5 and select the original iOS 4.0 firmware, not the one which you have just downloaded.
• Check “Install Cydia”. Leave the rest if you’re not sure about if you need it or not.
• Now turn your iPhone off and make sure that its plugged in to your PC. After that, hit “Next”.
• Now you will see some instructions in the Redsn0w application that would guide you about how to put your device in the recovery mode. That would include systematic press of Home and Power button. Simply follow them exactly with their lines until you see further processing.
• Thats it. Let the Redsn0w do its thing and when its done, your iPhone or iPod touch will reboot automatically and you will find it running on iOS 4.0.2. Thats the trick!