I use D6, because I'm told 4977 turns off the eject reset, which is dumb to me, as I don't want to hard-off my box everytime I want to change the game.
What would be good is if the bios changed the eject fucntionality to a reset if one were to double-press it.
Then again, those who complained about having to shut it off and turn it on for a reset when the system came out have apparently been silenced by their inepitude regarding xbe patching.