As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING APPROACH INTO SLC RECEIVED A FLAPS FAIL MESSAGE WITH FLAPS AT 20 DEGREES. RAN QRH PROCEDURE AND LANDED WITHOUT INCIDENT. FOUND LEFT BPSU TO BE JUMPY (TURNED SEVERAL TIMES WITH NO CHANGE IN POSITION). REMOVED AND REPLACED LEFT BPSU IAW 27-51-10 AND CHECKED LEFT AND RIGHT FLAP RIGGING IAW MM 27-54-00. P/N: 855D100-9, S/N OFF: 1530B, S/N ON: 1294B.