This guide assumes you have previous experience with hactool and messing with your NAND. You aren't supposed to blindly copy commands in this, so read before pasting!
Also, the Python sections require Python 2.7 and pycrypto.
- Open
sd:/Nintendo/contents/private
in a hex editor. - Copy the hex representation of it and put it somewhere for later.
- Mount your NAND's SYSTEM partition.
- Open
/save/8000000000000043
in a hex editor.