Hello Pete,
TS252R10-02 is MSA P2000 Bundel version TS252P001. The good news is you are not that far back from the latest released version. You can confirm the Storage Controller version by reviewing release notes.
Here is a link to the TS252P001 release notes: https://support.hpe.com/hpsc/swd/public/detail?swItemId=MTX_474cd8362e0e4ffea414bd8d50#tab4
My suggestion would be to restart the B controller which is currently down. You cannot upgrade that controller until it is back online. If you go into the CLI on controller A you could restart the B controller by issuing the following command:
# restart SC B
Once the B controller is online you can cofirm the firmware version and upgrade as necessary. For a quick reference of your controller, enclosure, and drive firmware please refer to the MSA Firmware site: https://h41111.www4.hpe.com/storage/msafirmware.html
Cheers,
Shawn
I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply.