Your SHIELD will automatically set to a HDR10 capable display mode when detected.

If you own a Dolby Vision compatible display at 4K resolutions with 60Hz refresh rate, enable Dolby Vision by selecting Settings > Device Preferences > Display & Sound > Dolby Vision

If you are unable to enable “Dolby Vision”, your HDMI cables may be the issue. Try replacing them with higher quality cables and try again.

If your TV supports 4K Dolby Vision at lower refresh rates, you can change your display mode at Settings > Device Preferences > Display & Sound > Advanced display settings > Custom display mode and select any mode labelled “Dolby Vision Ready”.