It is always best practice to take a backup of a chassis before making any changes especially a firmware update.
First of all access your desired chassis then go to;
Enclosure Settings > Enclosure Bay IP Addressing > Configuration Scripts
On the right hand side you will see;
SHOW CONFIG: Click to view a configuration script containing the current settings for this enclosure.
SHOW ALL: Click to view a script containing a list of the enclosure’s current inventory.
You can save the configuration files using notepad to somewhere safe. So these two files are used for the recovery if something goes wrong.
So when you need a recovery go to
Enclosure Settings > Enclosure Bay IP Addressing > Configuration Scripts again. On the left hand side;
You need to browse to locate those backup configuration files you have saved and upload them. It might take a while and after completion make sure everything is as expected.