The Solaris 10 10/09 release of Solaris is tested on all supported Sun systems running the latest combinations of the following:
BIOS and ILOM
SPARC Firmware and OBP and Hypervisor
For best results using the Solaris 10 10/09 release, upgrade your BIOS/Firmware to the latest release listed in the matrix at http://www.sun.com/bigadmin/patches/firmware/release_history.jsp.