[ame=http://www.youtube.com/watch?v=adVp-IxcDHI]YouTube - SHAttered AppleTV 2G[/ame]
Well, that didn't take long.
@MuscleNerd reported last night that he was able to use SHAtter to make the new Apple TV restore a pre-jailbroken IPSW. This video, released on the Dev-Team Blog, shows @MuscleNerd using ssh to access the Apple TV, running commands as root. According to @p0sixninja, it only took @MuscleNerd 30 minutes to do it.
The "not ready for prime time" jailbreak just shows what's possible, as there's no way to load and run apps on the Apple TV… yet. However, @StealthBravo has confirmed that you can mount the Apple TV in iTunes using a microUSB cable, and TinyUmbrella has already been updated to allow users to save Apple TV SHSH blobs. Late last night, @StealthBravo found DFU mode: plug in a microUSB cable (no power cord), hold the Menu and Down buttons for 6 seconds to reboot and then immediately hold Menu and Play buttons. The team is working with devs from the original Apple TV, and it looks like @nitoTV has a list of most if not all of the headers.
Things are about to get interesting. Make sure you pick up a microUSB cable when you get your Apple TV!
Source: Dev-Team Blog and Twitter