There are a number of 777's which we affectionately refer to as the GMIS aircraft. They are GE powered aircraft and the regs are in the ZZZ or VII range.
These aircraft are early delivery 777s and arrived into the fleet with what is called the GMIS entertainment system. Noticable onboard by the removable handset/phone with the red buttons on the back and smaller screens in WT. Unfortunately this company went out of business and never developed an upgrade system which would have allowed BA turn it into an AVOD system unlike the Rockwell Collins on the rest of the fleet. As a result BA will be hanging on to this system for a few more years until the Thales system is introduced at which time it is intended to gut out the current GMIS aircraft and replace the entire IFE with the new Thales system which is the same as the one being installed on the A380 and B787 fleet!