If it is from a UCS then you should be able to access those files on CCO with just a registered guest account without a SMARTnet contract attached to it.

I can't find anything for a N2XX-ABPCI02 though. It must be integrated into one of the big driver ISOs or packages.

What is the firmware portion that you can't upgrade? Most of the pieces I think are interchangable except the part that deals with the system management interfaces.