SD Filesystem

Overview

The 3DS uses an SD Card for general storage of game data, music, photos and videos taken with the 3DS.

sdmc
├── DCIM
└── Nintendo 3DS
    ├── <ID0>
    │   └── <ID1>
    │       ├── dbs
    │       ├── extdata
    │       ├── title
    │       └── Nintendo DSiWare
    └── Private
   

• Everything stored under sdmc/Nintendo 3DS/<ID0>/<ID1> is encrypted with console-unique keyslots, files stored under nand/data/<ID0> only use these keyslots for MACs. All CTR files under these directories use the keyslots initialized by nand/private/movable.sed.
• ID0 is the first 0x10-bytes from a SHA256 hash.
• ID1 is the scrambled SD card CID from the SD card which this directory was originally created on. To generate this directory name from the original CID, first the CID is rotated 8-bits to the left. Then, each u16 is moved as described in the below table:

Input rotated CID u16 index	Output CID u16 index
6	0
7	1
4	2
5	3
2	4
3	5
0	6
1	7

DCIM - Photos and Videos taken by the Nintendo 3DS Camera application are stored in this directory. Internet Browser image downloads are stored here too.

Note: Playing/Recording (3D) Videos was introduced with update 3.0.0-5. The 3D videos are in .avi format and the video frames use MJPG.

dbs - This contains database files relating to the titles installed on the SD Card. These files are encrypted. For more info, see Title Database

title - Title data for titles installed to the SD Card are found here. All data in this directory is encrypted with a console-unique keyslot. For a list of SD Card titles see the Title list. For more info on the title data structure see Title Data Structure.

Nintendo DSiWare - DSiWare titles are exported here.

Private

"Private" data is stored here as cleartext:

/Nintendo 3DS/Private/<Title ID Low>/

00020400 - Nintendo 3DS Camera 
00020500 - Nintendo 3DS Sound

Under the camera private dir is phtcache.bin. When you want to install and see pictures with 3DS, rename to 8 numbers.mpo and save it on /DCIM. Under the sound private dir is: voice/XX/*.m4a. Where XX is 01-10, with sound saved as .m4a.