Originally Posted by shayind4
Does anyone know whether firmware 5.1.1 is downgradeable to 4.4.2 or 4.3?
Samsung has bundled new SE Android features and may include a form of boot signing that may make rollbacks impossible.
But if you want to genuinely roll back you might be able to conjure up a solution with Odin 3.07. There might even be a possibility with Kies, if you have a back up that is on 4.3.
Nandroid is your best friend.