Hacking Problems with ACNL cartridge. Possible CFW solutions?

[Darlenix]

Excuse me if this isn't the correct forum. I wasn't sure where I could get help with this. Please move the thread to correct section if this actually isn't the correct subforum.

I have an ACNL cartridge, right? I lent it to a friend with a N3DS with the installed amiibo update. A few days ago, I got that cartridge back.

I used it in my old 3ds, without the amiibo update installed, and created a really neat town I'd like to keep.

The thing is, I used the o3ds out of need because I didn't have my n3ds(cfw'd with the amiibo update) available at the moment.

Now, I put in the cartridge in my N3DS and the save it has inside is the town of my friend. But MY town appears when I load it up in the o3ds.

I tried deleting my friend's town in the N3DS, but then the game warned me of corrupted data. The O3DS didn't recognize any save data anymore. Good thing I exported the save data just in case with JKSM, and things are back to before deleting it.

Any helpful soul that might throw me a bone here?

Here's an image of the same cartridge inside both 3DSs: http://puu.sh/wNiPs/2661dcdc25.jpg

 

[GizmoTheGreen]

when you first run the game with the update it creates a converted savedata with a different filename inside the savespace.
so I guess when you ran it without the update, the "old" game doesn't know about this new file and created a -new- save since it "didn't have any"
then when you ran the updated version it just continued on using the new savedata with the new filename.

old ACNL save is garden.dat, I think the amiibo update converts this file to garden_plus.dat if there is already a savefile, but it keeps the old one, I guess as a backup incase the conversion goes badly.

edit: might be relevant https://www.reddit.com/r/ACHacks/comments/6k634m/how_to_convert_save_data_gardendat_to_garden/