When Developer Mode fails

Greetings,
I'm new to this forum but I'm impressed with the content so far.
I have not been able to find a solution to my problem, and that is I can't get my Roku 2 into Developer mode.
HHHUURLRLR is not working. Nothing happens.
I hear all the beeps, try it slow etc but no joy.

Is there a reset that i can do to force into developer mode?

kaw