As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) UNABLE TO PRESSURIZE AIRCRAFT. RETURNING TO DEPARTURE. NO EMERGENCY DECLARED BY CREW. CABIN ALT HI EICAS WARNING MESSAGE ON WHILE CLIMBING THROUGH FL250, PACK 2 APPEARED NORMAL, OFV SHOWING FULLY CLOSED. PACK NR 2 AIR SUPPLY DUCT FOUND WITH HOLE IN IT. REPLACED AIR SUPPLY DUCT. LEAK CHECK AND OPS CHECK CARRIED OUT SERVICEABLE.