Can I Downgrade iPod touch 3?

Downgrade to iOS 4.1 is Currently Supported
Apple is currently signing multiple iOS versions simultaneously. This temporary signing window overlap allows you to restore your iPod touch 3 to the older build(s) listed below using a computer without encountering verification errors.
September 3, 2010
April 27, 2012
February 29, 2012
November 8, 2011
October 7, 2011
July 21, 2011
July 14, 2011
May 2, 2011
April 12, 2011
Can I downgrade from an iOS Beta on iPod touch 3?
Yes. If your iPod touch 3 is running an iOS Beta, you can always restore back to the latest signed public release using Recovery Mode in Finder (Mac) or iTunes / Apple Devices (Windows).
Can I downgrade to the iOS version iPod touch 3 originally shipped with?
No. Apple permanently closes the signing window for older releases. Even though iPod touch 3 originally launched with an earlier version, Apple servers will no longer authenticate that installation.
What can I do if I cannot downgrade iPod touch 3 but experience battery or performance bugs?
You can perform a clean restore to the latest signed firmware using a computer to eliminate software glitches and corrupted cache, or await the next minor point update from Apple that includes targeted bug fixes.
Can I downgrade iPod touch 3 if the signing window has closed?
No. Apple servers reject restore verifications for unsigned builds (returning iTunes Error 3194). Unsigned firmware cannot be installed on standard Apple devices.
Will restoring or downgrading iPod touch 3 erase data?
Yes. Flashing an IPSW firmware file requires a restore that wipes on-device storage. Ensure your personal data is backed up to iCloud before proceeding.