If that hypothesis is true, how do some of the factory builds, like sabrina, manage to switch hdr on and off properly as needed?
I realize that this hdr issue has been a problem in various certified amlogic builds for years, but a few devices have fixed it. How was it fixed in those builds?
Do you have a SABRINA? Fortunately, I don't, but all other devices use Amlogic's DROIDLOGIC subsystem which gives control to things like HDR_POLICY. Sabrina may not need Droidlogic to make HDR function properly if all the Droidlogic TVsettings, like HDR_POLICY, were hardcoded or hooked into the stock com.android.TVsettings.apk .
You familiar with the TiVo Stream4K (S905Y2), it used {HDR_POLICY=1} as default when it was on Android 9, but when they pushed out the Android 10 Q update the default is now {HDR_POLICY=0}, which I hate; but all these settings "should" be End-User selectable via DROID_SETTINGS vendor app if the software engineer took the time to go through Amlogic code and doesn't just build the firmware as-is. And with the TiVo at least it gives access to some of the Droidlogic coding, but not all; with its HDR settings hardcoded into the TVsettings.
So, if I choose to watch HDR content on the TiVo, I have made an ACTIVITY shortcut with the tvQuickActions app to activate its HDR_POLICY setting overlay manually. The Activity that toggles HDR_POLICY inside the TiVo is found inside the package:
com.droidlogic.tv.setttings
as a DolbyVision setting.
ADB shell command to toggle the setting:
Code:
am start 'com.droidlogic.tv.settings/com.droidlogic.tv.settings.display.dolbyvision.DolbyVisionSettingActivity'
But, that same shell command used with a stock Amlogic device without the DolbyVision license, will give two options: Enable or Disable. You
DO NOT want to enable it, possible Green screen of death for the Onn.4K if enabled, or at least that what I believe seeing as the Onn.4K didn't block access to DolbyVision setting activities last I checked in its stock original firmware releases.