Yesterday MuscleNerd, a member of iPhone Dev Team, confirmed Apple TV jailbreak using the SHAttered exploit. Though it is still unclear what we can do after the jailbreaking and how we can run the apps on Apple TV, but the day is not very far when we will be able to run third party apps on it because Steve Jobs has already indicated that an Apps Store for Apple TV could be opened in near future.
Lets come to our original topic. DFU mode is a special mode in iPhone/iPod/ipad and now in Apple TV that allows to interact with iTunes without loading the iOS installed on the iDevice. This mode is very helpful in the situations when we need to upgrade or downgrade the Apple TV with a custom firmware (eg created by PwnageTool and or Snowbreeze).
Here is How to Put the Apple TV into DFU Mode:
Note: You will need a micro-USB cable to connect your AppleTV with PC.
Step 1: Plug the ATV (apple TV) with MicroUSB.
Step 2: Hold menu+down for 6 seconds to reboot.
Step 3: Then immediately hold Menu+Play to go into DFU mode.
This method is posted by StealthBravo on Twitter and I can’t confirm it because I am still waiting for my Apple TV to arrive.