Having lived and flown round China, I always thought the sound of the undercarriage coming down was a cue for
all Chinese passengers to turn on their mobile phones.
(Like touchdown is a cue to release seatbelt get up and retrieve handbaggage!)
So, mobile phones are highly unlikely to be connected with this incident else there'd be B777s landing short everyday in the Far East.
I hope I'm right. Else think of the implications...