Green-dot.
"PEDs also have specs but what happens to those specs if the user has dropped his PED once or twice on occasion, perhaps damaging it but is still functioning? "
In my experience PED are normally built to a price, not a spec; as such. A/C, are generally still built to a spec and that includes all the electronics. If that spec is adequate, is a different question. However, the B777 is a very safe A/C.
In a different field, I once had to investigate a problem of a little old lady with voices coming from her kettle! Yes, its was true, voices were coming from her kettle. Quickly traced to a unusual combination of resistance/capacitance/inductance in the kettle was de-coding "our" radio transmissions. We provided a new kettle, end of problem. Just to illustrate PED are built to a price, any spec (unless it adds "bells/whistles") is secondary.
Barrymung.
I concur!
Previous AAIB investigations seem to indicate 3 or more items are required to fail before an accident results. Perhaps, only perhaps, EMI was 1 of the 3?