Apple TV 2 help please. Black screen!

Originally had 4.1.1 and run latest seasonpass but just had black screen after two attempts even though the jail breaking ran smoothly
I had to do an iTunes update to get it working again so it’s now on 5.2.1?
What next?
From reading here it now looks like the only option IFF it works is tethered which is no good as its not for me so will obviously have to unplug it at some time

Help!