This tutorial is only for previously jailbroken iPTF3G users who have accidentally upgraded their iPod's to 3.1.3 firmware and can no longer jailbreak. 1. The first step you will need to take is to display hidden folders on your Mac. (if you already have them enabled, skip to step 2) Clicking here will redirect you to a tutorial on how to enable hidden files on a Mac. 2. In finder, navigate to your main disk, then navigate to the /ect folder. 3. In the /ect folder you will find a file called hosts. Copy hosts to your desktop. 4. Make a duplicate of hosts on your desktop, and rename it hosts_backup (for safe keeping). 5. Open hosts (the one on your desktop)" with text edit. 6. Add Code: 184.108.40.206 gs.apple.com just below the last line, and double check to make sure it is correct. 7. Hit Apple + S to save the file. 8. Navigate back to the /ect, and delete the currently present hosts file (it will make you confirm) 9. Take the newly created hosts file from your desktop, and drag it into the /ect folder (it will ask for confirmation again) 10. Place your iPod into DFU mode. 11. Click here to be redirected to a tutorial on how to do this if you don't know how already. 12. Plug your iPod into your Mac. 13. Click here to download the iPod Touch 3.1.2 firmware. 14. While holding the alt key, click the restore button. 15. Select your just downloaded iPod Touch 3.1.2 firmware. 16. Wait for the restore to complete, then you will have a successfully downgraded iPod Touch 3G!