The Firmware Upgrade feature allows the following upgrades while the Primary CPU controller continues to control the process:
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Operating System of the Standby CPU
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upgrading the firmware in the Standby coprocessor
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upgrading the firmware in the Standby CRP module
However, during the upgrade, the system is not redundant.
Upgrading Firmware without Stopping
Under normal operating conditions, both controllers in a redundant system must have the same versions of firmware. There are checks by the controllers to detect if there is a mismatch in firmware.
Normally, when a mismatch exists, performing a Switchover is not be possible because the Standby CPU controller is not allowed to go to the RUN Primary mode.
However, to allow a firmware upgrade without stopping the application, set the Command Register system bit
%SW60.4 to 1.
NOTE: Enabling the firmware upgrade without stopping the application overrides the process of checking whether the Primary CPU and Standby CPU are configured identically.
As soon as the firmware upgrade is finished set %SW60.4 to 0 for an upgrade without stopping.
NOTE: An upgrade is only possible if the firmware used is compatible the target hardware.