Although I have figured out the admin password, and telneted into the modem over the LAN, I can't do admin things like "install" an updated firmware.
I have attempted to use the CLI port rather than telnet. I tried using a commercially made RJ45 to 9pin console cable but no-go. So I have made up a CLI to serial port cable but I don't get any response out of the CLI port at all. There shouldn't be any difference between telnet and CLI port.
I also want to close of the MngtVCC port to eliminate the possiblity of anyone getting into my modem.
Does anyone have hands on experience with using the CLI? Has anyone succeeded in "installing" new firmware using telnet or CLI?
I found that I had to get to the <MON> prompt by sending "m" then "o" via the CLI interface. From this prompt, various useful (read dangerous) commands are available.