As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL - FLT 564 - EN ROUTE, PHL TO GLA - AFTER TAKEOFF, FLAPS WOULD NOT RETRACT PAST 1 UNIT WITH THE FLAP HANDLE IN THE UP POSITION. EICAS STATUS MESSAGE, "FLAP/SLAT ELEC", WAS INDICATED. THE FLIGHT RETURNED TO PHL AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE FLAP SLAT ELECTRONIC UNIT. OPERATIONALLY CHECKS OK.