Some things that I believe are "facts".
1) Engine/airframe data is sent via satellite, specifically the Iridium system
and 2) Iridium, being originally designed as a satellite "cell phone" system, would continually ping satellites, even if data wasn't being sent, or phone calls not made.
So even if Boeing, or the airline, or RR weren't getting data, that doesn't mean that the Iridium network doesn't have a good idea where the aircraft is, pretty much all the time. At least if the hardware was powered up. Even if they didn't have an active Iridium subscription, wouldn't the system keep track of the receiver, if only to be ready to give it a subscription code?
Cell phones ping towers almost constantly so as to maintain a connection in case a phone call is made. The system has to know what tower (or satellite) has the phone in view, so your phone can be made to ring within seconds of a phone call.
Lots of assumptions here, but some lights are coming on.