AppleInsider discoverd a growing thread at the Apple Support Communities website where users report issues after updating their Apple TVs (2nd and 3rd generation) to the latest Apple TV 5.1 software. It looks like many Apple TVs are getting bricked after running the update:

After running the software update option on the Apple TV, a number of users indicated that the hardware simply displayed a blinking light, while nothing but a black screen is shown on their HDTV. Others found that their Apple TV could no longer connect to their network after updating, rendering the streaming-centric device useless.

According to AppleInsider, manually downgrading the Apple TV software to version 5.0.2 has been discovered to work as a possible fix:

The process requires installing an IPSW restore file from Apple, plugging the Apple TV into a Mac or PC with a micro USB cable, and force restoring the software through iTunes.

Remember that if you’ve previously saved your Apple TV’s firmware signatures (SHSH blobs) using TinyUmbrella or aTV Flash (black), you can downgrade Apple TV 2 software using Seas0nPass.

Here are the IPSW restore files:

Apple TV 2:
http://appldnld.apple.com/AppleTV/041-4362.20120605.t8i4U/AppleTV2,1_5.0.2_9B830 _Restore.ipsw

Apple TV 3:
http://appldnld.apple.com/AppleTV/041-4361.20120605.grjot/AppleTV3,1_5.0.2_9B830 _Restore.ipsw

Apple TV software update 5.1 has been released on September 24, 2012. The biggest changes included support for Shared Photo Streams, the ability to switch between iTunes accounts and to send audio content from Apple TV to AirPlay-enabled speakers and devices

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Downgrading to older version of Apple TV 2 firmware just got easier, thanks to a new version of Seas0nPass. Recently released by FireCore, Seas0nPass 0.8.2 uses previously saved firmware signatures (SHSH blobs) to jailbreak and restore an Apple TV version that Apple may no longer be signing.

Backing up signatures using TinyUmbrella has been possible for quite a while. Last week, FireCore added this feature to aTV Flash (black): version 1.3 automatically backups Apple TV firmware signatures to the cloud. New Seas0nPass works with local signatures as well as those saved online.

Here is how to downgrade to older version of Apple TV 2 firmware using Seas0nPass:

Note: you can downgrade the firmware only if you’ve previously saved your Apple TV’s firmware signatures using TinyUmbrella or aTV Flash (black).

1. Connect AppleTV via USB
2. Launch Seas0nPass
3. Right-click the ‘Create IPSW’ button and select your desired version.
4. Seas0nPass will handle fetching saved signatures and restoring the firmware automatically.

If you’re receiving a ‘not eligible’ message, this means Apple is no longer signing that particular version, and Seas0nPass was unable to locate any saved signatures for that device/firmware combination.

Seas0nPass (both Mac and Windows) is available as a free download from Seas0nPass.com.

You may also want to read:
aTV Flash (black) 1.3 for Apple TV 2 released
How to install aTV Flash (black) on Apple TV 2
AirPlay Mirror your Mac’s screen to Apple TV with AirParrot

Visit What's on iPhone for the best iPad and iPhone app reviews!
Do you want to feel like a wizard? Check the Kymera wand in Amazon: You can control your Apple TV waving a wand!