The airliner was carrying lithium-ion batteries in the cargo hold. These have caused fires on aircraft before. And it seems a little more plausible than that "black hole" theory.

Quote
...In rare cases, aircraft have been destroyed as a result of fires started from the devices, although they have been cargo planes in both incidents.

In one case, UPS Airlines Flight 6 crashed while attempting an emergency landing in September 2010 en route from Dubai to Cologne in Germany.

Billie Vincent, the former head of security for the U.S. Federal Aviation Administration, said the revelation re-affirmed his belief that flames started in the cargo hold, destroying the aircraft's communication systems then filling the cabin with toxic fumes.

This, he says, would have overwhelmed the passengers but may have given the pilots a chance to divert the aircraft for an emergency landing.

He told Air Traffic Management: 'The data released thus far most likely points to a problem with hazardous materials.
Onward and upward,
airforce