From the (always impeccable) BBC:

Key statement from the Boeing executive:

Boeing has admitted that it may never know what caused the battery malfunctions that resulted in all its 787 Dreamliner aircraft being grounded.

It is not uncommon not to have found the single root cause. So industry best practice is to look at all the potential causes and address all of them.

Except the use of Lithium based batteries. That problem remains.

Boeing have fixed all foreseeable problems. Again. (All the problems were already all fixed when the Plane was designed).

Pity about the unforeseen problems. Or the one which remains because of Boeing’s denial.

The Boeing Dreamliner – The Self-Immolating Airliner. Oh well, I suppose death will be quick.