As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED PACK 2 FAIL WHILE ON THE GROUND ALONG WITH BURNING SMELL IN THE COCKPIT AND CABIN AFTER PUSHBACK. EMERGENCY VEHICLES DID RESPOND, AND REPORTED NO ABNORMALITIES WERE NOTED OUTSIDE OF THE AIRCRAFT. MAINTENANCE TROUBLESHOT PER EMB AMM AND PLACED PACK 2 ON MEL 21-51-00-1.