The above does not work in reality- This code is more or a less a hacked layer on top of b2g-desktop... Reading through https://github.com/alivedise/gaia/blob/16f855ed9faae376a38bea5c2ddfbe803cc50d64/apps/system/js/orientation_manager.js#L36-L51 this should work just fine... Eventually we will have real orientation via marionette https://bugzilla.mozilla.org/show_bug.cgi?id=804515