You are not becoming mad, the NSS4000 was discontinued long ago so you won't be able to find the firmware on the cisco page any longer, I'm sorry.
Maybe somebody else o the forums will know of website where it can be downloaded from but I would be very cautious as there will be no way to know if its the original firmware from Cisco or if it was modified.
I hope this was helpful.
i own a NSS4000, and i might have the firmware still around.
im sorry, im kinda of a '2nd back-up' type (y)
due to this kind of 'EOL/EOS' policy of a lot of company's
so if you'd like, i can search the drives for you
Did you have any luck in finding the firmware for the NSS4000? I'm stuck in the same boat and have been running in circles for hours.
Any help would be appreciated.
As much as the NSS4000 is an absolute piece of sh!t that I cannot wait to jettison, I do have the original 1.21.0 FW saved. I've put it online here for d/l: http://www.mediafire.com/download/p8fodvktk0t893o/NSS4000_FW_1.21.0.tar.gz
If it saves anyone even the slightest frustration with this stupid machine, I'll be happy.