Fun fact, KOReader is too smart and does hardware button rotation. With the original framework doing the button rotation too, the buttons work incorrectly in inverted mode.
With the patched framework, KOReader works correctly, but not all the other apps.
At the moment, I reverted to the unpatched framework and patched KOReader instead.
See
https://github.com/koreader/koreader...ent-1316262571.