As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOI - CRUISING 23000 FEET MASTER CAUTION AND "ELEVATOR FEEL" CAUTION LIGHT. AUTOPILOT DISCONNECTED ATT FAIL HDG FAIL ON FO'S PFD AND HDG FAIL ON FO'S MFD. FMS INFORMATION ON FO'S MFD DISAPPEARED. MSG ON FO'S FMS SAYING SOMETHING ABOUT AHRS 2. DIVERTED TO BOI. LANDING UNEVENTFUL. REMOVED AND REPLACED AHRU NR 2 COMPUTER, OPS CHECKS GOOD. RETURNED TO SERVICE.