Lay Theory
The 777 supplies (3rd Party) Fuel to any of several engine types. In the case of the GE, where fuel icing is addressed in the design, there have been no reported rollbacks, so at first blush, the uphill path is RR's. But it is not that simple. Sub contractors for design, materials, manufacturing, testing, delivery, spares supply, transit, indemnity, Fuel, SOPS, ............
The list is long. Welding subs, branched and subrogated claim, maintenance, etc. etc. The Room will be full.
AF