blank screen after "sleep"

I have an atv2 current f/w.  I jailbroke it, and installed Black as per the Youtube video.  All prompts were seen and replicated along the process.  Firecore button showed up.  Logged into my iTunes account etc. All good until it went to sleep, now it will not wake up. sits there and just blinks with a black screen.  I DID NOT UNPLUG THE POWER cable.

 

Have written Firecore, anyone else have a helpful guess as to what went wrong?

I suspect that it is wating for a tethered boot.   However I have no idea why it should be in that state if power was never lost.

 

that’s my thinking as well.  Odd though, as it tell me I have successfully tethered booted, or whatever the diaglog box states after a successfull boot.  I would have assumed I’d gotten an error code.