I have an Epson ink tank printer which keeps telling me that new firmware is available. I won't let it download, though. It would probably make the device worse.
I never had a problem with updates on my Epson, but having bad experinces with other products, I can understand your concern. I don't remember now if there was an option to disable updates or not, but when I last reorganized my home network, I put all untrusted devices including this printer in a no-gateway subnet. It can't call home, check or download anything. The only problem is that scanning to computer from the printer panel is based on multicast, and I couldn't figure out how to route that yet.
