Why does the Nios II Cyclone II full featured reference design suffer from a memory corruption problem?

Description The Nios^® II data cache controller with a line size of 16 or 32 bytes per line will cause memory corruption in rare cases. Nios II Development Kit version 5.1 service pack 1 does not share this issue, however the Nios II Cyclone^® II full featured reference design is not updated by the service pack. In order for the data cache issue to be corrected, open SOPC Builder and regenerate the design followed by a recompilation in the Quartus^® II 5.1 tool. For more information about the Nios II data corruption issue please refer to the Nios II Development Kit Version 5.1 Errata.