Quoted from Gunnder:
Just so I understand how this works before I proceed:
Can I take out the official SD card that is in there right now that has the official 1.13 code on it, put in another SD card and then install the custom code? That way I can just swap out SD cards if I want to go between official and custom? Or does something else get written elsewhere other then the SD card which would prevent me from doing this?
And I guess the 2nd part of this question is, if the above can be done, does that mean that all current settings and current high scores will be saved on the original SD card and once I swap it back after trying the custom code, all my settings and high scores will remain as before? Or is all this information written elsewhere?
No, you cannot use an empty sdcard and install into it with a USB. The sdcard has the boot loader code in it which mounts the USB interface.
Yes, you can swap out the standard and custom code by swapping the sdcards. The scores are bound to the card so they will be tracked independently.