Silicon Graphics TP9400 RAID Owner's Manual page 33

Controller Enclosure Components
If a controller canister fails, the Controller Fault indicator on the affected controller
canister will glow. For more information about indicators, see "Checking the Controller
Enclosure Indicator Lights" on page 36.
When you replace a failed controller, and if certain NVSRAM bits are set, the firmware
on the new controller is automatically synchronized with the firmware on the second
controller (the one currently managing the array) controller. This ensures that the
controller firmware level is the same on both controllers after a replacement. You do not
have to download new controller firmware after replacing the controller. See the storage
management software (TPSSM7) for information on these bit settings on your system.
The Controller Fault indicator blinks while the firmware is being synchronized. The
status indicators on the controller blink in a moving pattern to indicate a serial
download. Do not remove the controller until the automatic synchronize process
completes.
Warning:
Avoid damaging the controller. If the controller is removed or if power is
interrupted before synchronization is complete, the controller being updated may fail,
and you will need to replace it.
007-4304-003 13