As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER GEAR RETRACTION, HAD A HYDRAULIC 1 LOW QUANTITY MESSAGE ON EICAS, FOLLOWED BY AN E1 HYD FAIL MESSAGE ABOUT 15 MINUTES LATER. THE QRH WAS FOLLOWED AND THE CREW DECLARED AN EMERGENCY, MANUALLY EXTENDING THE LANDING GEAR AND LANDED WITHOUT INCIDENT. THE AIRCRAFT TAXIED TO THE GATE WITHOUT INCIDENT. MAINTENANCE INSPECTED THE NR 1 HYDRAULIC SYSTEM AND FOUND THE HYDRAULIC HOSE FROM THE UPPER ACTUATOR ON THE E1 THRUST REVERSER LEAKING. THE HYDRAULIC HOSE WAS REPLACED ALONG WITH THE ENGINE DRIVEN AND ELECTRIC MOTOR DRIVEN PUMPS AND FILTERS WITH NO FURTHER LEAKS NOTED.