As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#1844, BGI-BOS. (AIRCRAFT DECLARED AN EMERGENCY AND DID AN AIR TURN BACK TO BGI). 'EIU 1 FAIL; LGCIU 1 FAIL, MULTIPLE ABNORMAL ECAMS ND ALERTS. UNABLE TO DECIPHER WHICH PROCEDURE TO FOLLOW. DELARED EMERGENCY AND RETURNED TO BGI. LANDING WAS NOT OVERWEIGHT; REMOVED & REPLACED LGCIU# 1 AS REQUIRED IAW AMM 32-31-71. OPS CHK NORMAL. RAN ENGINE AT IDLE NO DEFECTS NOTED.'