Outstanding point. Unless I'm missing something here, this would seem to me to dismiss the tire theory.
That would leave us with an electrical fire in the cockpit, and raise again the questions that have been asked already:
Is there a fire suppression system on board?
How much redundancy is there in the circuitry (e.g. could a fire in one location knockout everything?
If the answer is yes, why are these huge planes built in this manner (such that an electrical fire in one location disables all communication with the plane)?
Why wouldn't the fire just rage on and take out everything - such that there would not be an additional several hours of flight?
It was reported that the new flight path was entered into the computer. Is this how a rapid change in course would be handled in an emergency?
If the cockpit of one of these huge planes is disabled, do the flight attendants have any means to communicate with the ground (assuming that not everyone was disabled within a short time frame)?
How does autopilot work? Does it get feedback on location from GPS satellites etc? If so, would there be no record of this - if the plane flew on with autopilot?
FYI.
http://en.m.wikipedia.org/wiki/Nigeria_Airways_Flight_2120
When the landing gear was retracted, “burning rubber was brought into close proximity with hydraulic and electrical system components”, causing the failure of both hydraulic and pressurisation systems that led to structural damage and loss of control of the aircraft.