With the release of Oracle Hardware Management Pack for Oracle Solaris 11.3 (SRU10), the man page for the fwupdate states that the new sysfw target replaces the sp_bios target going forward. For Oracle Solaris 11.3 SRU10, both targets continue to exist; sysfw for SPARC systems and sp_bios for x86 systems (and can also be used for SPARC for backward compatibility with existing scripts).