As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SFO - CREW REPORTED BOTH FLIGHT MANAGEMENT COMPUTERS DISPLAYED "STANDBY ONE" AND ALL NAV FUNCTIONS (INPUTS) WERE LOCKED OUT. BOTH ROUTE 1 AND 2 UNUSABLE. FLIGHT RETURNED SFO LANDED WITHOUT INCIDENT. REPLACED THE NUMBER 1 FLIGHT MANAGEMENT COMPUTER. SYSTEM GROUND CHECK NORMAL OPERATION.