As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 9225, IAH-PHL - A MAINTENANCE FERRY FLIGHT WITH AN INOPERATIVE GENERATOR RECEIVED APU LOW OIL PRESSURE AMBER ALERT ON EICAS. AFTER CONSULTING THE QRH IT WAS DECIDED TO RETURN TO IAH. UPON LANDING THE APU FAIL LIGHT ILLUMINATED AND THE APU AUTO SHUTDOWN. MAINTENANCE FOUND THE APU OIL QUANTITY LOW AND SERVICED APU AS REQUIRED.