iOS 6.1.6 for iPod 4 Touch [verified]

1. Back up your iPhone or iPad with either iCloud or via iTunes
2. Launch iTunes on your Mac or PC
3. Make sure you're on the latest version of iTunes. Go to About and then Check for Updates or visit iTunes.com
4. Plug in your iPhone, iPad, or iPod touch if it isn't already
5. Click on iPhone, iPad, or iPod in the top left navigation
6. Now while pressing SHIFT key, Click on the Update button in the first section that contains information about your device — alternately you can click restore instead if you'd like to do a clean wipe with updated software
7. Browse your downloaded ipsw (this torrent) and press Open
8. An update should be recognized, click on Update in the popup menu and agree to any terms or conditions
9. Unlock your device with your passcode if prompted in order to continue with the upgrade
10. That's it. Simply leave your iPhone, iPad, or iPod touch plugged in and let iTunes do its thing. Once your device reboots, you should be running iOS 6. Just be sure you don't disconnect until iTunes is done..