I’m having the same problem. I have tried a tethered jailbreak so many times I’m about to give up. The out come of the tethered try is a message that the atv does not appear to be jailbroken when attempting to install ATV Flash and the untethered resopnse is a flashing led and black screen. I get the “not jailbroken” message when installing ATV Flash even though SeasonPass tells me my ATV is now jailbroken.
I have been at this since yesterday afternoon with no joy. I was able to get the 4.4.2 version to jailbreak on the same ATV2 but not with 5.3 and I have tried everything posted on these boards.(Mac) I really do not want to have to go back to 4.4.2 and lose all the new ATV functionality (HBO go, ESPN, etc) but is that my only choice? I have been using this software since the orig ATV 1 without problem and I really don’t think I’ve forgotten how to follow the directions to Jailbreak. But this is so frustrating. And by the way I do keep the ATV powered after JB while I plug in the HDMI and ethernet to reconnect to tv.
I did upgrade to 5.3 without thinking about a month ago and then had to wait unti yesterday when a jailbreak (?) was available but no joy for me at this point. Is this latest update working for others who need to jailbreak ATV2 running 5.3?