Same for debugging V3. Okay, so take a screwdriver and pull out the screw on back of your Tama. Now you'll need a really tiny screwdriver to pull out the four screws, under that first layer.
Here be careful that you don't mess up your Tama. See a half-circle that says 'Debug'? Good. Rub it 10 to 20 times with a pencil. Then screw everything back in.
If this helped, now you can pick out your own character!