As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RECEIVED MULTIPLE EFIS COMP MON ON TAXI AND TAKEOFF. AT 12000 LOST FMS, AHRS; UNABLE TO FLY GREEN NEEDLES FOR 10 MINS. ABLE TO RETRIEVE GREEN NEEDLE CAPABILITY AFTER 10 MINS. A/C RETURNED TO ATL AFTER T/O. PILOT CANCELLED EMERGENCY DECLARED/TOWER ROLLED EMERGENCY VEHICLES AS A PRECAUTION.