One thing need to know is, the flashcart save date cannot be used directly between different flashcart. If you have a r4i gold 3ds flashcart, and played some games, there are same backup files and save data files in your sd card. And then if you get a dstwo in you hand again, can you use the backup files and save datas in the dstwo directly? No, you need transfer the files first.
How to transfer the files? It need a software tool, named: DSSaveTools, here is how to use it:
1. Download the DSSaveTools. Unzip it.
2. Start the .exe file, you will see the follow picture:
5. Click the “change”, it will transfer the save date.