Because these enhancements require modifications to both the System ROM and the flash update utility, the May 2011 (or later) System ROM cannot be downgraded using the flash components available on the HP Support site that are dated earlier than May 2011.
However, the System ROM can be downgraded by creating a new flash component using an older System ROM revision. For more information on how to downgrade the System ROM, see the HP Support website at http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?locale=en_US&objectID=c02838375.