For those of you needing to pull the plug and then plug it back in to have your TV see a signal, note that you can hold both the Menu button and the Home (TV) button on your atv4k Remote for about 6 seconds and it will cause your atv4k to cycle power off and bak on. This will only save you a trip to your physical plug to get the signal.
On the other hand, even though I am convinced that in future Apple will find a software fix for this issue, I actually exchanged my apt4k at the nearest Apple Store because I was within the return period. When I connected the new atv4k to my TV i have seen no sign of the problem.
One has to realize that the Customer has no way to actually totally Restore an atv4k. In other words, you cannot actually reload the Operating System or Clear the atv4k completely and start from scratch. You can only Reset the atv4k which is not the same. Consequently if this issue is truly a software issue where some corruption or other flaw occurred in manufacturing you can't really do anything to resolve or mitigate this. On the other hand if this is a Hardware issue, which it probably is not, you can't do anything about that either. I have no idea if the Apple Store or an Authorized Apple Service Provider has the capability currently to totally Restore the atv4k in the field as yet.
My feeling is that if your connected atv4k is showing a great picture when the signal is viewable on your TV, your HDR appears to be working correctly, and your sound is correct then the wakeup signal issue is probably not your cable or your Settings on either Device (i.e., the atv4k or your tv).
