Why do my Nios II system instructions get corrupted when Nios II ECC error occurs ?

Description

Due to a problem in the Quartus® II software version 13.1,  if the Nios II processor is configured with ECC enabled,  ECC errors can cause invalid instruction cache operation. The invalid instruction cache operation is the result of the ECC corrupted instruction word.

Resolution

This problem has been fixed beginning with the Quartus II software version 14.0.