This is a GREAT post over at Reddit ANYONE who takes upgrading code on Cisco UCS as BAU.
ALWAYS have serial access to a UCS logged in and watch the process of FI’s upgrading and rebooting. Have “Restoring from bricked FI” as part of the backout plan and practice in a lab.
I noticed this post because it has links back to http://realworlducs.com/
Sobering and entertaining stories of upgrades gone wrong at below link.
Can honestly say “Been there, done that, have the t-shirt”