Telnet to 8080 fails (8085 works fine)

This is puzzling... I have been happily telnetting to port 8085 (debug) on my Roku, but cannot connect successfully at all on port 8080 (to run genkey). I've tried everything I can think of. It connects immediately, but no matter what I type, it drops the connection as soon as I hit return.

Has this happened to anybody else?