I seem to recall some discussion (elsewhere?) as to various dislikes of the current functionality of that button.

The only problem is that once you've used it to do the "user accepts responsibility" thing at the after-boot-full-screen-info-screen, it always toggles to "Off" after that.

For instance, Let's say I boot it in the car. It's fullscreen info:Track. I press and hold the bottom button and it goes to the screen it was on when I powered down last time, which was Transient. All well and good. But now that it's in Transient, it would be nice if it would toggle back to Track. But it doesn't, it toggles back to OFF.

Now, as much as I'd like to see you actually do something about this in your kernel hacks, I would like to warn you that I think the empeg guys might be working on changing this behavior and you might not want to mess around with that button's behavior until their work has settled down (after beta).