sd
└── Nintendo
├── Album
├── Contents
└── save
The file structure of an SD card in the Nintendo Switch looks like the tree above. The files are contain two parts, one is the Album and the other one is the ROM file of the games. You can manage these files in System Settings -> Data Management. In the Move Data Between System / microSD Card, you can move ROMs to your SD card, which will be saved in the path Nintendo/Contents/registered. And in the Manage Screenshots and Videos, you can move your Album data to Nintendo/Album. That’s all. You cannot transfer the game Save Data to the SD Card. You can only Teransfer them to another NS or upload to the cloud when you subscribe the Nintendo Switch Oneline.
If the file system format is correct, you do not need to format a new SD card when you insert it. However, to create the initial file structure, you still need to insert the SD Card and restart the NS. After that, you can copy the data from your old SD card to the new one.
You could copy the year/month formatted folders under the album folder to your card. And copy the rom folders under the path Nintendo/Contents/registered, but do NOT copy the private and private1 file in the folder Nintendo/Contents, it will not be readable by the NS if you do that, especially if your two SD cards are not the same size or speed. Finally, don’t forget to copy and replace the file 8000000000000000 and 8000000000000124 in the path Nintendo/save, it stored the file structure of your SD Card.
