Ok guys, finally got Netflix 4k working on my Mi Box S paired with Mi TV 4S (Global). Yay!
Should have listened to my own advice above lol.
The "Enhanced HDMI setting" is only available when you press the center button of the Mi TV remote when you are in the HDMI input of the Mi Box S. It will show greyed out otherwise.
Once i turned on HDMI enhanced, i was able to see 4k 60z under resolution settings.
As bro whoooo mentioned above however, whether the HDMI range is set to full or auto, has no effect on my 4k. In fact i prefer the colours when it is set to auto, setting it to full, looks abit washed out (my opinion).
Final couple of questions if anyone can help:
1) I realised after changing the resolution to 4k 60hz, i lost the option for 10 bit colour. Now only 444 8bit and 420 8bit. Not that it matters but should i choose 444 or 420? And does anyone know why the 10bit option disappeared?
2) Mi Box S is still screen flashing randomly (usually before the autoplay of preview) but works flawlessly once the video is playing. Does anyone know how to fix this? Saw another bro facing the same problem above.
3) Test pattern works great - showing 4k resolution now. But i see some titles in HDR and some titles in 4k Ultra HD (far less titles in 4k though) - is this normal?
Thanks all for the help! Been a tiring past few days but finally got 4k to show in Netflix for Mi Box S + Mi TV 4S combo!
Got a HDMI cable on the way but cost me $2.22 (Amazon Basic cable) so nothing much lost.
P.S. Honestly can't tell the difference between 4k and HDR but since bought a 4k TV, feels good that Netflix is able to show "4k Ultra HD". w00ts!