Mobile material error (show only black)

By the way,

iPad 3 has only OpenGL ES 2.0, not 3.0.
But I made a quick sample in Unity (the same cube with materials) and worked, so I think OpenGL ES 2.0 supports the “PBR”, even fake.

edit: Also, with preview set to ES2 in UE4, it works as well (screenshot attached)

So, what can be done for works in UE4 (in device)?

Thanks!