This issue is fixed in Oracle Solaris 11.2 SRU 5.
When updating the Sun Storage 12 Gb SAS PCIe HBA, Internal firmware using fwupdate, you might get an error similar to the following:
Error: Firmware download failed for component Extended Error: Firmware upgrade attempt failed ERROR: Firmware download failed for component
Workaround
Reboot the system and the firmware update will be applied.