Latest news regarding Dreamliner crisis
The cause of the problems presumably lies with the batteries of the planes. The FAA is still investigating the incidents.
However, Boeing has sought permission of the FAA to operate test flights with the Dreamliner planes. This could be an indication that Boeing found a solution to the technical issues. It is not clear yet if the FAA will grant their request. It obviously will take a while before airlines will be able to use the Dreamliner airplanes for passenger flights.