I have set my rotation to ONLY use Landscape right but on iPad Unity displays it correctly at first but then after about a seconds displays the Landscape image (Legacy Launch Images>iPad Landscape/Retina image) in portrait mode while the game gets loaded. I am using Unity 5.3.3 f1.
In the SplashScreen.mm file I also tried to set:
static ScreenOrientation _nonOrientableDefaultOrientation = landscapeRight;
…but that did nothing. The screen seems to always go into portrait mode only during the splash sequence.