First of all, AWESOME NEWS! I was delighted to find your email about the beta availability in my email this morning.
Shortly after, i was browsing my twitter stream and discovered this article, which describes how to jailbreak the new 4.2 firmware:
If i jailbreak my ATV using the above method on 4.2, is it possible to use the ATVFlash beta?
Or will i f#ck things up? :-)
Thanks and best regards,