As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: STATUS MESSAGES: WEATHER RADAR SYS L+R,EICAS MESSAGE WEATHER RADAR SYS, BOTH RADARS INOP. DECESION MADE TO RETURN TO SCL, OVERWEIGHT LANDING WITHOUT INCIDENT. MAINTENANCE REPLACED THE RIGHT HAND ISS PROCESSOR UNIT IAW AMM 34-42-08.