flashing light on Apple TV

Have you tried restarting your Apple TV using the remote?

http://support.apple.com/kb/HT3180

Also this see Apple article if the above does not work:

http://support.apple.com/kb/HT4380

And this:

http://support.apple.com/kb/HT4367

HI I just wanted to say that unplugging the ATV from the power source for 30 minutes (not seconds) worked for me. I found the solution on another thread and it seems to be the solution for a few people.

its in recovery mode plug it into a pc or mac

I have 4th Gen. Plugged into Mac using USB-C cable and BAM! It’s off to the races! :-) They make it pretty easy to set back up using your iPhone credentials.