If there is no valid data currently stored on the array from where you want to remove controller, you delete the volumes and vdisks first, then run the factory restore defaults command. I would then power down the system correctly and remove all power cords. This will flush all the buffers.
You can use command "restore defaults factory" and "restore defaults"
Then you can move one of this controller to the working system. Better to do this in downtime and after movement update firmware to same code what Controller B was already running.
Hope this helps!
Regards
Subhajit
I am an HPE employee
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