As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH F/O EFI PUSHED IN ALT, THE COMPARATOR FLAG ON F/O EADI BLINKING ON AND OFF AND GPWS EICAS AND TERRAIN SYSTEM STATUS MSG WAS BLINKING ALSO. THEN F/O EADI AND EHS I WENT BLANK AND STAYED BLANKED, UNTIL THE EFI SW WAS PUT BACK TO NORMAL. FOUND CTR SYMBOL GENERATOR FAULTY SWAPPED CTR SYMBOL WITH RIGHT SYMBOL GENERATOR. FAULTS FOLLOWED. REPLACED AND OP CHECKED RT-SYMBOL GENERATOR PER MM, TEST PASSED.