I'm pretty sure it's C69, I remember discussing this once, but I believe that is the side that B_M is connected to already. If you look on the back of the board, you can probably locate the two large 3.3v traces, and how they both lead up to the cart slot, which is where it is cut off at. Scrape, flux, and solder a short but thick wire across there and tada. I also think you can accomplish the same thing by reconnecting 3.3v to the 3.3v pin on the switch.
SS