I bought a 4k dreamscreen diy last year. It has been working fine for a year on my 1080p tv. Recently upgraded tv to a 4k and now it doesn’t work properly. It works fine for about 3 mins then the lights in back start flickering after another 3 mins or so both the tv screen and dreamscreen flicker on and off for another 3 minutes or so then the dreamscreen lights turn off completely and the tv is picture is fine. But once that happens then the sound cuts out every 5 seconds for like one second. Any ideas on how to fix this. My new tv is a tcl 55s421. My hdmi goes from my cable provider to my xbox then to dreamscreen hub then to the tv. This set up worked fine for old tv but not the new 4k one.
This looks more like a HDMI cable issue. Try to replace to a 4K/8K HDMI cable. Also try to disable HRD in app and in TV. Since you said that it worked will with a HD TV, I am ruling out the possibility of hardware damage, unless it got damaged during fixing on new TV.