As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW HAD AN EICAS MESSAGE BACK UP GEN RT CMC MESSAGE TO SAM INDICATED OIL PRESSURE LOW. FLIGHT RETURNING TO FIELD AND LANDING OVERWEIGHT. THE RIGHT BACKUP GENERATOR (BUG) AND BACKUP GENERATOR CONVERTER WERE REPLACED. THE FINAL FIX WAS TO REPLACE THE BUG WIRE HARNESS PER AIRCRAFT AMIS HISTORY.