When I turn on "HDMI UHD Color" for the input to which the NUC is connected, TV says "No Signal". HDMI UHD Color is needed for 3840x2160 @ 60Hz with 4:4:4 chroma and presumably configures the HDMI port as 2.0. When the PC boots - no splash screen, no BIOS (after pressing F2).
If "HDMI UHD Color" is OFF, everything is fine, splash screen appears, and then BIOS (if I press F2). TV reports 3840x2160 @ 30Hz and the splash screen is apparently in 4K.
Similarly, in windows. When I switch to 60Hz (with "HDMI UHD Color" ON) I get black screen and then "No signal".
It looks like when the HDMI port on the TV is configured as 2.0, NUC sends it something, which the TV does not understand.
TV: Samsung UE40MU6100 (similar US version: UN40MU6300).
Cable: AmazonBasics High-Speed HDMI Cable, 6 Feet or 3 feet - Meets the latest HDMI standards (4K Video at 60 Hz, 2160p, 48 bit/px color depth); supports bandwidth up to 18Gbps.
Thanks