As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT AIR RETURNED TO PHL ON ACCOUNT OF RIGHT HAND GENERATOR OFF AND APU FAIL INDICATION. PILOT REPORTS LOST THE RIGHT GENERATOR 2 HRS INTO FLIGHT. FOLLOWED QRH PROCEDIRE AND RESET. R GEN OFF EICAS CAME BACK ON 1 MIN LATER. MAINTENANCE REMOVED & REPLACED RIGHT ENG IDG IAW AMM TASK 24-11-01-004-001-004/404-002-004. OPS CHECKS & LEAK CHECKS NORMAL.