So, I updated my Roku Ultra 4k device the other day, and the it suddenly decided it wasn't going to connect to my wifi no matter what. I ended up doing a factory reset, and the roku loading logo would show and the audio for it would play, but as soon as I got to the setup portion, the display cut out and the sound still worked. I ended up setting it up on a different TV, and then brought it back. By the way, I've tried all of my HDMI slots (3) and have tried 4 different HDMI cables. I can get the display to come up if I carefully finagle it in a specific way, but any videos I try to play end up with black displays again while the audio still works. If it's not in the HDMI slot perfectly and the input switches to the Roku or the TV turns on, the homescreen will display briefly before cutting out again. Thank you for your assistance.