I have been in the process of upgrading our UCS to firmware version 2.0.3b. While I read through the Cisco doc I still didn’t have a great feel for what the upgrade would entail. I did some searching and found the following two links which I think lay out the process really well and make it easy to understand along with some concepts that aren’t as straight forward as I thought they could be.
Actual upgrade of a chassis:
Difference between Activate and Update on the firmware management tab.
I hope this help someone else out and make life easier for them.