Rat, Boeing, Rolls, and the NTSB are on-site and involved in the investigation, granted in an 'advisory' role - the local authority will be prime. So at some level Boeing knows what's going on. As I've mentioned previously, everyone involved is under something of a gag order - all information release should come through the local authority. Even around Boeing, information sharing is on a 'need to know' basis - in part to avoid leaks although it also comes in handy when the inevitable lawsuits start popping up.
That's why I can publicly post about it - I literally know nothing about the investigation (insert poor Sargent Schultz imitation here
). If I was in the know I'd need to STFU.
When the final report comes out, if Boeing or Rolls feel they've been unfairly thrown under the bus, then they can publicly disagree with the report - not before (see the Egypt Air 767 for a prime example).