After 2 years of owning the TV, I finally discovered how to get HDR working consistently on it. I have the TV attached to a Yamaha TSR 7810 and mainly use it with an 4k firetv attached to the receiver. I had to do the following:
1) Set TV's 4k Signal format to [email protected]
(Settings --> Inputs --> Format Settings: HDMI 4K signal Format)
2) Set 4K FireTV Display settings to following:
Video Resolution: Auto (up to 4k Ultra HD)
Match Original Frame Rate: On
Color Depth: Up to 10 bits
Color Format: Auto
3) Set Yamaha TSR 7810 to Video Mode --> Processing --> Resolution --> Through
Now to actually get HDR to kick in, I have to start playing something in HDR from the firestick (usually just go to netflix and play an HDR movie). Then with the HDR video running, turn TV off and then back on and it will be locked on HDR mode. Alternatively, I can also cast an HDR video to the firestick from my phone and it should turn the TV on and be in HDR mode, but with the CEC on the TV also being buggy, it doesn't always auto turn on when I start casting to the firetv. The cool thing is, even once I stop the HDR movie and play something with a lower resolution, the TV will stay locked into HDR. I think the bug with it not auto switching into and out of HDR mode actually helps us out here! It looks like HDR mode goes away if you change inputs, turn it off, or go into settings. Now I just need to find some good HDR video calibration settings because the colors are way too intense in HDR mode.
Maybe others already knew this trick but I was never able to get it working consistently before. I know a lot of people use an Apple TV 4k with the Chinese firmware to stay locked into DV mode but I decided against messing with the firmware because I use OTA broadcast channels (actually bought the apple TV still sitting new in box..lol).
I had actually been considering going the same route as
and trying to get a refund from my credit card company because the inconsistent washed out picture was really starting to bug me. But maybe this will hold me over now...I have until Feb 2021 to file a claim so still might.