The whole board. If your camera is crappy, zoom in as close as you can and take several pics if you have to to cover the whole thing. I get the feeling you had no business playing with a soldering iron, and solder can splash, jump, and pretty much end up anywhere. You may have multiple issues.
@AnalogMan seems to have figured out your nand problem. I still think you have another problem with your hard-mod attempt. Your nand problem wouldn't be cause for not being able to mount your SD (only your ability to read/decrypt stuff in the "/Nintendo 3DS" folder).