As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 828, EN-ROUTE THE CREW RECEIVED A GREEN SYS HYD FAILURE MSG & ENG 1 GREEN HYD PUMP LOW PRESS LIGHT. OPERATIONAL DECISION WAS MADE TO RETURN. AFTER AN UNEVENTFUL LANDING, THE ACFT HAD TO BE TOWED TO THE GATE. REPLACED A GREEN SYS HYD PRESS LINE.