Mt, yes, I have the 940c.
I woke up this morning and low and behold Amazon 4K videos are now working. Also the 4K HDR videos are working but I still can't get the HDR to work. It doesn't automatically select it and when I manually select it, it doesn't stay, soon as I go back to the show it reverts back to the Picture Mode I had it set on before I manually selected HDR. Also I noticed that the picture looks a bit dark and not what I expected 4K to look like, so I am wondering if I am even watching 4K even though it shows that it is Ultra HD and HDR in the description. I tried hitting the display button to see if it would show me the resolution but the display button doesn't work. Maybe the display information doesn't work with streaming? Ken, could you please let me know if the display button works for you when you are watching Amazon shows when you get it working. To be honest the shows on Amazon that are HDR look the same as when I am watching a 1080i show on my DTV but a darker picture and maybe not even as good. This may have something to do with the fact that it is HDR and I am not able to watch it in that mode. When I watch a 4K show that is not HDR, like "Orphan Black" the picture is back to the brightness that I am use to seeing when I am watching my DTV, however it isn't as good as some of the 4K you tube videos I have viewed. At least I have Amazon working now and the non HDR 4K videos look good, just not as good as You Tube 4K videos. I hope that the HDR issue is a software issue and can be corrected with a firmware update, but since others have reported that there HDR is working as it should I wonder about that.