HDR not working when "allow 4k" is disabled

Hi i Will try what u dat here

Just 1 question u disable HDR

U let allow 4k on off?

Finally, I took my Xbox one s to my friend's house and connected it to a 4K OLED TV. And I can see the 4K and HDR signals working fine. I used the same HDMI cable that was connected to the 4K projector. But when connected back to the projector and selected
the option Allow 4K I see the message the TV doesn't support 4K. But Allow HDR is fine on the Projector. I don't know where the issue is. The projector seems to work fine with Apple TV 4K, Firestick 4K and nVidia Shield TV with 4K HDR signals. The issue seems
to be with the Xbox the way its detecting the signal on the TV.

Of course, disabling HDR defeats the whole purpose of purchasing 4K HDR Blu-Rays.

you need hdr for 4k output

Actually, you don't.

Uhd and hdr are required for 4k output

You need UHD, in the sense that you need the TV to support 3840 x 2160 resolution, but you don't need HDR enabled to reach 4K. UHD 4K is the amount of screen resolution available measured in pixels, HDR is the ability of the TV or monitor to display more
natural colours.

Note that the Xbox One S can do HDR in games that support such a feature, but regardless of what resolution you set, all games max out at 1080P internally. If the display is 4K, it will remain in 4K, but games will only be upscaled. Only the Xbox One X
can play Enhanced titles in 4K natively.

You should be able to disable HDR, how you disable it depends entirely on your TV. Disabling HDR via the TV settings should not disable 4K screen resolution. Indeed, some Xbox One games do not support HDR, Fallout 4 on the One X can play in 4K for instance,
but it does not support (or indeed have an option for) HDR.

On my Sony Bravia Android based TV, I had to go to the main settings and enable HDR functionality. Even then, I had to set the HDR setting to 'Auto' on the HDMI port I have my console connected to. If you have HDR set to 'On' all of the time, non HDR games
will display the wrong colours, look oversaturated. With 'Auto' enabled, HDR will only operate when it detects an HDR supported game. This may not be a feature of your display however.

What make and model is your TV?

I think I have been able to resolve the issue on the S by disabling the advanced video settings (Turn off Allow 4k and HDR) and set the video output to 1080p and 8bit.