I want the Android to only know landscape, portrait is something that does not exist.
I tried using this (adb user_rotation value change): https://stackoverflow.com/questions/25864385/changing-android-device-orientation-with-adb/43093208 which only affects the apps. The native UI is still portrait.
I tried this (manipulating the system/build.prop ro.sf.hwrotation): https://www.tinkerboarding.co.uk/forum/thread-574.html. This kept the UI in landscape but I then needed to also use the method above (1) to force all the apps to rotate. However the touch functionality was still in portrait. Note: In the link above the values listed are not correct.
I tried looking through the engineering mode to see if I could manipulate the settings there but I'm not finding anything that could be related to the orientation.
We've tried apps that force landscape mode but they are not low level enough.
Is there any way to just completely eliminate or permanently disable portrait??
This is a Mediatek custom build (chipset: MT6737M) running Marshmallow 6.0. It is rooted.