As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 634 SFO-BOS, CREW DECLARED AN EMERGENCY DUE TO GEAR DID NOT EXTEND HAD TO DO MANUAL EXTENSION. ALSO HAD A L/G NOT DOWN AND LOCKED ECAM. PER TSM 32-31-00-810-808-A FOUND ISOLATION/SAFETY VALVE TO BE AT FAULT. REMOVED AND REPLACED ISOLATION/SAFETY VALVE PER AMM 32-31-17. OPS AND LEAK CHECK GOOD.