As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INTERMITTENT "FIRE DET 2 FAULT" DISPALYED ON STATUS MAINT PAGE. OBSERVED 3 HRS INTO FLIGHT. REMOVED AND REPLACED THE ENGINE FIRE DETECTOR GEAR BOX, REF AMM 26-11-03-4-1. REMOVED AND REPLACED THE ENGINE FIRE DETECTOR UPPER RT TURBINE, REF AMM 26-11-03-4-1. PERFORMED ENGINE RUN PER JRH SECTION 5. NO FAULT SHOWN. OPS CHECK GOOD.