As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS - ENG 2 FIRE LOOP B FAULT INTERMITTENT ON CLIMB OUT. PER PFR SHOWS ENG 2 FIRE LOOP A + B AGC FAIL, PERFORMED 26-12-00-810-894-A. ALL WIRING CK INSULATION CK OK ON BOTH LOOP A AND B. RESISTANCE CK WITHIN LIMIT. VISUAL CK OK. REMOVED AND REPLACED #2 FDU PER AMM 26-12-34-400-001-A. OPS CK OK. OK FOR SVC.