With the latest announcement about the FDR being normal until the event, it seems that neither the FDR nor the CVR will provide any useful information, other than that the initial event involved severing the cables to the recorders.
This could be an event that, initially, just severed the cables (along with associated structural damage) and that subsequent break-up events were 'not recorded' rather than being simultaneous.
What could sever the recorder cables (first).