I have roku 4 ultra connected into yamaha 679 -> LG 4k TV. occasionally I get purple warning screen regarding hdr and note to look roku.com for fixes. I have replaced all HDMI cables, turned them around, changed amplifier ports and TV ports. In most days hdr and 4K content work just fine, but every now and then the purple screen pops up. (I have changed amplifier setting from 2 to 1, before anyone says anything).
Solution is to *hard* boot (unplug ROKU power cable) roku and everything starts working. rebooting Yamaha does not fix anything so that leaves Roku under the radar. I have latest ROKU code and latest Yamaha code.
Anyone has found any solutions for this other than replacing ROKU with something else ?