So I've successfully jailbroken my AppleTV using these instructions

How-To: Jailbreak Apple TV 2G on iOS 4.2.1 with PwnageTool

Of note I had to use iReb from ih8sn0w to install the package I built with pwnage through iTunes with no errors. And I had to use OSX 10.6



UNFORTUNATELY I can get neither wifi nor ethernet usage rendering the device essentially useless. I was wondering if anyone had had some success with this matter.



Additionally I gave this a shot

Downgrade with no SHSH , no host files edit 4.0.2 – 4.01 | Mobile Phone Files Download

where you put an old 4.1 build into a 4.2.1 package and as long as I used iRed and the tiny-umbrella server on my own computer(172.0.0.1) instead of the itunes authentication sever it makes it almost all the way through until I get a 1600 error at almost the end of the process.



ANYONE WITH ANY INSIGHT ON EITHER DEVELOPMENT I'D LOVE TO HEAR IT. THANK YOU. Or any other forums to post questions to. Thanks

The downgrade without SHSH link has long been confirmed as fake/not working.

Jailbreaking the ATV2 on 4.2.1 is still pretty much an advanced topic, supposedly a few things have helped recently (primarily the ability to VNC control the ATV2 without HDMI connected).

I personally don't yet own an ATV2 and right now am still happier with my more hackable ATV1 that with a BCM70012 (Crystal HD) card can do more than the ATV2 can right now.

Originally Posted by Olethros

The downgrade without SHSH link has long been confirmed as fake/not working.

Jailbreaking the ATV2 on 4.2.1 is still pretty much an advanced topic, supposedly a few things have helped recently (primarily the ability to VNC control the ATV2 without HDMI connected).

I personally don't yet own an ATV2 and right now am still happier with my more hackable ATV1 that with a BCM70012 (Crystal HD) card can do more than the ATV2 can right now.

I also have an ATV1 with the BCM70012 card. Really nice, especially under Linux. It can do a heck of a lot. But that Plex app running on my ATV2 (4.2.1 jailbroken) is really nice. Perhaps in a week if I have to go through that tethered boot again I will have 2nd thoughts, but for now the ATV2 is (almost) at the likability level of my ATV1. Both are really nice. The ATV1 with the CHD card is really incredible. I just find it works better when running it from Linux and then you lose a lot of the neat things that you get under OSX.

ls

Originally Posted by lstep

I just find it works better when running it from Linux and then you lose a lot of the neat things that you get under OSX.

I do agree with this, it's a difficult compromise. I prefer the ATVOS for many things. However it's only under linux that the combination of more free RAM, BCM70012 and inbuilt GPU really shines.