HISENSE-BUG1:

Verified Affected TV Sets: 2023 55U8K, 2023 65U8K, 2023 75U8K, 2023 85U8K, 2023 100U8K, 2024 55U8N, 2024 65U8N, 2024 75U8N, 2024 85U8N
Affected Firmware Versions: 55U8K_55U8N_55E85GUA_O0730.zip, 55U8K_55U8N_55E85GUA_O1030.zip, 55U8K_55U8N_55E85GUA_P0414.zip

Bug Description: All HDR picture modes other than HDR IMAX have completely wonky EOTF tracking, resulting in a very overly bright picture and impossible to calibrate HDR settings on a Desktop in windows.  You can work around this by forcing auto low latency to on, and then setting the profile to IMAX, but it's still a pretty major bug.  Somehow the IMAX HDR profile is immune, even in low latency game mode.  Note that you must set low latency game mode or Chroma 444 support is lost on the IMAX profile.

Possible Workarounds: This is actually part of a larger problem with EOTF tracking on this set, although most firmwares mask it to the point of irrelevance.  For the 55" GoogleTV U8N/K sets at least it is possible to fix this by entering the service menu and calibrating the EOTF manually.  You can do this by following the directions below:

1.) Hit the "settings gear" on your remote.

2.) Select "All Settings."

3.) Select "Display and Sound"

4.)  Drill down to "Sound," "TV Sound Effect" and finally "Advanced Settings."  Hover over the "Balance" area but do not select it.

5.) Hit "123" button to bring up the number input.  Enter "1969" and wait (fun fact Hisense was founded in 1969).  It should activate Service mode.  Press back a few times to get out of anything that may be open.  Then press Menu.  You should now be in the Service Menu.  Be careful here, it is quite dangerous if you hit something you shouldn't.

6.) On the directional pad, hit right once, then down until "Picture Curve" is highlighted.  Now press right one more time.  You are now in the curve editor and may use up down to navigate, left and right to adjust values.  

7.) Using the above knowledge of how the menu works, configure your screen to look exactly like the picture below.  Please bear in mind you are only configuring brightness and contrast entries.



8.) Once you have finished, "Menu" key saves and backs you out of the menu with a few keypresses.  Once you are completely backed out you can exit by simply turning your TV on and off.  Be advised that this disables notification access to the GoogleTV launcher and deletes any wifi APs for some odd reason, so you may want to fix that upon restarting.