In a Wall Street Journal article that mostly covers proposed new rules for transporting Lithium batteries, this section was of interest:
The UPS jet's flight-data recorders have been downloaded by U.S. crash investigators, and early analysis is consistent with the theory that the blaze started in a cargo area, spread quickly and then pushed smoke into the cockpit, preventing pilots from seeing their instruments.
On Tuesday, investigators from the United Arab Emirates gave the strongest public signal yet that the blaze originated in the cargo hold. They disclosed that prior to smoke in the cockpit, there was a fire warning received by the crew. Such warnings normally come from sensors in or around the cargo compartments, not inside the cockpit
Tighter Curbs Expected on Lithium Batteries - WSJ.com