Anyway,
This accident will demand a lot of work from investigators.
A detailed knowledge of the A320 Thrust Control System, TLA reading, hardware/software interfaces, etc. I think that at the present status either a HF or electronical/mechanical problem have the same probability.
Maybe the CVR shows something but I am not too confident on that.
If the Thrust Levers at least had some independent sensors at the TL track this investigation might not be that difficult. A TL motion could be detected independently of a change in the TCU TLA reading.