How can I upgrade a DOCSIS 1.0 cable Modem firmware to Version 1.1?

Simply put, as an end user, you cannot (technically, you prob. could, but plan on it getting overwritten and you'd need to have some good knowledge about the modem in general). The firmware for the cable modem is typically specified in the config file that is sent down by your cable provider isp. One thing you'll want to look for is that your modem is indeed upgradeable, which shouldn't be a major issue nowadays.