Originally Posted by B1tK1t
Your friend told you the right thing. Netflix on the Shield don't support 4K resolution at 24Hz for either HDR Ultra HD or SDR Ultra HD.
If you set your Shield to 4K/24Hz it shrinks from Ultra HD to 1080p and doesn't go further. This is a known bug since the first nougat update.
Amazon HDR and SDR Ultra HD works at 4K/24Hz. About Vudu I can't tell you any.
4k and 24hz works on mine for netflix. A while back someone said it wasn't working so I switched the shield to 24hz, loaded up netflix and started a movie playing, brought up the info screen and there it was 4k. If I come back to it another time then 4k won't work and I have to reboot to get it back again.
Though I tend to not leave it at 24hz as I don't see any difference.
Streaming Devices: Nvidia Shield TV, 2x Roku 3's, 1st and 2nd gen chromecast, Amazon Fire TV stick 2nd gen, Apple TV 4, xbox 360, xbox one
Displays: Vizio M602i-B3, LG OLED65B6, panasonic ax100u on a 145" S-I-L-V-E-R painted screen, 40" Samsung(don't recall model #)
Receivers: Denon X3300, Yamaha RX-V663. Bluray/UHD player: Oppo UDP-203
Retired - HTPC: Intel e6300 2.8ghz, Intel DG45ID, 2gb DDR2, Radeon 5570, MCE IR receiver