Aura ONE Is my Aura dead? Battery or firmware?

Hi

My Aura ONE working ok when connected to power. But once disconnected go blank, like on the clip... http://www.youtube.com/watch?v=DXbjP0iKdpM

But it started two weeks ago after firmware update, started going corrupted each time I've put it on sleep mode, execpt that I could read books and it was fine, however battery were going down quite fast...

So I wonder is it battery or something with firmware? I've tried downgrade but behaves same way.

Regards