As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF ROLL, CREW RECEIVED A DUAL IRS FAILURE WITH ALL RED FLAGS APPEARING. BOTH THE CAPTAIN'S AND FIRST OFFICER'S SCRATCH PAD SHOWED "IRS NAV MOTION FAULT". CREW DECLARED AN EMERGENCY, CIRCLED THE FIELD AND THEN RETURNED TO THE FIELD AT MHT. FLIGHT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REALIGNED AND TESTED BOTH IRU'S PER MM 34-28-31. AIRCRAFT OK FOR SERVICE.