To implement an environment compatible with NIST 800-131A, you must be running Flex Version 1.3.2.
Firmware for Flex Version 1.3.2 is available at the following location:
http://www.ibm.com/software/brandcatalog/puresystems/centre/
Click the Systems updates tab.
After updating firmware to Flex Version 1.3.2, follow the instructions in When using an IBM Flex System Manager or When using the Chassis Management Module (CMM) to set up an environment that complies with NIST 800-131A.