As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RIGHT PFD / DU NR 4, ATTITUDE FAIL, HEADING FAIL, EVENTUALLY DU BLACKED OUT. FUMES IN THE COCKPIT. DU CAME BACK ON BEFORE LANDING. TROUBLESHOT TO BAD DU NR 4. REPLACED DU NR 4 AND DOWNLOADED FILES TO DU NR 4 IAW CE680 M/M 34-23-00. OP'S CHECK GOOD.