We have upgraded 100 switches a few weeks ago and ran into some problems. I'd recommend you test it first with a switch before you roll it out on a larger scale.
What we found was that when we say "upgrade the secondarty but do not reboot automatically" as firmware compliance Central did not change the boot partition.
Then when we clicked the reboot to finish the upgrade, it rebooted the old software, then copied the new image into the primary image and then rebooted again. The result was both images were the new image and we got two reboots.
When you set the primary partition, Central did not copy the active image to the secondary first.
Don't know if that was fixed in the meantime. I would test it with a test group first.
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Thanks,
Bjarne
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