As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOI - ON FLIGHT 4276, RETURNED TO GATE, RIGHT PACK CAUTION MESSAGE AFTER ENGINE START CYCLED PACK SWITCH MESSAGE RETURNED. MAINTENANCE INTERROGATED MDC FOUND RIGHT FLOW CONTROL VALVE INTERMITTENT ON TAXI. REMOVED AND REPLACED RIGHT FLOW CONTROL VALVE. AIR CONDITIONING SYSTEM OPERATIONAL TEST GOOD. DURING LEAK TEST OF AIR CONDITIONING DISTRIBUTION SYSTEM FOUND RIGHT HAND BACKS PRE-COOLER CRACKED AND LEAKING. REMOVED AND REPLACED PRE-COOLER. OPERATIONAL TEST GOOD. AIRCRAFT RETURNED TO SERVICE.