This page describes the format and encryption of extdata, "extra data" stored on SD card and NAND, at:
ExtdataID-High is always 00000000 for SD, and always 00048000 for NAND. Regular apps can only mount SD extdata using the same extdataID which is stored in the CXI exheader. Therefore, regular apps which have the exheader extdataID set to zero can't use extdata. This restriction doesn't apply for shared extdata with extdataID high bitmask 0x48000 stored on NAND. System apps with a certain access right can mount arbitrary extdata. All NAND extdata is shared extdata, while all SD extdata is normal extdata.
All data in this page is little-endian. All "unused / padding" fields can contain uninitialized data unless otherwise specified.
To avoid confusion, the terms device directory / file and virtual directory / file are used with the following meanings:
- Device directory / file are the real directory / file stored on SD / NAND that can be seen under path
- Virtual directory / file are directory / file stored inside extdata virtual file system, which can be seen by applications in the mounted extdata archives.
An extdata consists of several device directories and files, which forms a file system consisting of multiple virtual directories and files.
An extdata with ID
ExtdataId has the following device files:
- All device files are DIFF containers. All format description below is about the inner content of the containers. Please unwrap these files first according to the DIFF format description before reading them using the extdata format description below.
Quota.datis only observed existing for NAND shared extdata.
<SubFileID>are 8-digit hex strings.
- Device file with
SubDirID = SubFileID = 00000000doesn't exist. Other ID combinations can exists.
- Device file with
SubDirID = 00000000and
SubFileID = 00000001is the VSXE metadata file and must exist.
- Other files, besides
00000000/00000001, are normal sub files, are these device files one-to-one correspond to virtual files. They contain raw virtual file data in the DIFF inner content.
SubDirID = 00000000is usually the only one device directory that can be seen. See #Device Directory Capacity for more information.
The inner data of
Quota.dat is 0x48 bytes with the following format. The exact function of this file is unclear.
|0x08||4||0x1000, block size?|
|0x0C||4||Always 126. Probably device directory capacity. See the #Device Directory Capacity more information.|
|...||The meaning of other fields is unknown|
Device Directory Capacity
A device directory in an extdata (a
<SubDirID> directory) seems to have a maximum number of device files it can contain. For SD extdata, this maximum number seems to be hard-coded as 126. For NAND extdata, the number is probably indicated by a field in Quota.dat, which is, again, always 126 as observed. 3DS FS tries to put all device files in the device directory
00000000 if possible, and only when more than 126 files needed to add, a second device directory
00000001 and so on are created. However, few extdata have such amount of files to store, so the behavior lacks of use cases to confirm.
The number 126 is probably from some kind of other capacity of 128 with
".." entries reserved. It is theorized that this is to keep a FAT directory table, with 0x20 bytes for each entry, in one 0x1000 cluster. The motivation is unclear.
VSXE File System Metadata
The inner data of
00000000/00000001 consists of the following components
- VSXE header
- Directory Hash Table
- File Hash Table
- File Allocation Table
- Data region
- Directory Entry Table
- File Entry Table
|0x08||8||File system Information offset (0x138)|
|0x10||8||Image size in blocks|
|0x18||4||Image block size|
|0x28||4||'Action' made on most recently mounted Extdata image|
|0x30||4||D of most recently mounted Extdata image|
|0x38||0x100||Mount path, from most recently mounted Extdata image|
|Below is File system Information, which is assumed following the same layout as Savegames#SAVE_Header|
|0x13C||4||Data region block size|
|0x140||8||Directory hash table offset|
|0x148||4||Directory hash table bucket count|
|0x150||8||File hash table offset|
|0x158||4||File hash table bucket count|
|0x160||8||File allocation table offset|
|0x168||4||File allocation table entry count|
|0x170||8||Data region offset|
|0x178||4||Data region block count (= File allocation table entry count)|
|0x180||4||Directory entry table starting block|
|0x184||4||Directory entry table block count|
|0x188||4||Maximum directory count|
|0x190||4||File entry table starting block|
|0x194||4||File entry table block count|
|0x198||4||Maximum file count|
- All "offsets" are relative to the beginning of VSXE image. All "starting block index" are relative to the beginning of data region.
File Allocation Table & Data Region
These function in the same way as the file allocation in savegames. However, the only two "files" allocated in the data region are the directory entry table and file entry table, so the data region is usually pretty small, and the file allocation table is unchanged once created and has no free blocks. Thus, the offset and size of directory / file entry table can be found directly by
offset = entry_table_starting block * data_region_block_size + data_region_offset and
size = entry_table_block_count * data_region_block_size
Directory Hash Table & File Hash Table
These function in the same way as those in savegames
Directory Entry Table
This functions in the same way as the one in savegames. It lists all virtual directories in this extdata.
File Entry Table
This functions in a similar way as the one in savegames. It lists all virtual files in this extdata. However, the format of a (non-dummy) file entry is a little bit modified:
|0x00||4||Parent directory index in directory entry table|
|0x04||16||ASCII file name|
|0x14||4||Next sibling file index. 0 if this is the last one|
|0x2C||4||Index of the next file in the same hash table bucket. 0 if this is the last one|
Each non-dummy file entry corresponds to a device file. The path to the device file is generated by the following computation:
// See previous section about this capacity const uint32_t device_dir_capacity = 126; // entry index is the index in the file entry table, with the first dummy entry as // index = 0, which is never used for a real file. // file_index = 1 is reserved for the VSXE Filesystem Metadata itself, so real files // started from file_index = 2. uint32_t file_index = entry_index + 1; uint32_t SubDirID = file_index / device_dir_capacity; uint32_t SubFileID = file_index % pdevice_dir_capacity; char extdata_path[...]; // ".../extdata/<ExtdataID-High>/<ExtdataId-Low>" char device_path[...]; // output path sprintf(device_path, "%s/%08x/%08x", extdata_path, SubDirID, SubFileID);
When mounting extdata, the unique identifier is used to match the ID stored in subfile's DIFF header. If the ID doesn't match, mounting will fail.
Virtual File System Structure
When extdata is created, these are always created regardless of whether the title actually uses them.
/iconThis virtual file contains the extdata icon displayed in data management. This icon can only be written to by titles when creating extdata, titles would have to recreate extdata to change the icon. This file can't be read directly, instead it is read via FS:ReadExtSaveDataIcon.
/user/This virtual directory contains the title's actual extdata files.
/boss/This virtual directory can contain SpotPass content. SpotPass content can only be downloaded to this
User extdata and SpotPass extdata use separate mount points at
/boss. Therefore one mount can't access the other virtual directory, and also can't access
/icon.(The title's SpotPass extdata can be mounted by the title itself, if it uses SpotPass)
Other optional but notable directories include:
/user/ExBannerThis virtual directory can optionally store extended banners. When this is available, this banner is displayed instead of the CXI ExeFS banner.
COMMON.binstores the common exbanner, while
<regionlang_code>.binstores an optional separate region/language specific banner.(regionlang_code can be "JPN_JP", "USA_EN", etc)
Usually the ExtdataID low is in the format '00<Unique ID>'
|JPN ExtdataID||USA ExtdataID||EUR ExtdataID||Description||Extdata images|
|00000082||0000008f||00000098||Home Menu extdata, this contains home-menu savedata and cached icons for applications.|
|00000200||00000210||00000220||System Settings extdata added with 2.0.0-2.|
|00000207||00000217||00000227||Mii Maker, contains an ExBanner||cleartext|
|00000208||00000218||00000228||Streetpass Mii Plaza||11 mb big!|
|00000209||00000219||00000229||eShop, contains store music in AAC format.|
|0000020d||0000021d||0000022d||Face Raiders, likely contains an ExBanner|
|000002cc||000002cd||000002ce||Home Menu theme|
|?||000004aa||000004ab||Nintendo Video Extra Data
This is where the video files are stored, and includes the thumbnail, the description, and possibly some checksum info in each video file stored in the extdata images. There are always 9 files within the subdirectory "00000000" of this folder, even without any videos downloaded. The files are "00000001" - "00000009", and "00000003" - "00000008" have the same filesize of 50.7 MB. It is possible to restore the older videos by overwriting all the files within this directory. Provided of course you have made a backup of the files before hand, by copying all the files within this directory to your computer. As far I'm aware its not possible to mix and match the files in order to get certain videos in one grouping, ie. having all 3 Zelda orchestral recordings in one group of 4 Nintendo videos.
|00000306||00000308||00000307||Mario Kart 7|
|0000030b||0000030d||0000030c||Nintendogs + Cats|
|00000305||0000032d||0000033c||Super Street Fighter IV 3D|
|00000328||00000358||0000033b||Ridge Racer 3D|
|?||0000034d||00000402||Samurai Warriors Chronicles|
|?||0000034f||0000038a||Dead or Alive Dimensions|
|00000481||N/A||N/A||Monster Hunter Tri G (Download-Quests)|
|?||?||000007af||New Super Mario Bros. 2|
|?||00000863||00000864||Animal Crossing: New Leaf|
|?||00000a85||00000a86||Professor Layton and the Miracle Mask
Professor Layton and the Azran Legacy
German Version ExtdataID is 00000a87
|?||?||00000b4f||Fullblox / Crashmo|
|?||?||00000ba9||Pokémon Mystery Dungeon: Gates to Infinity|
|00000c73||00000c73||00000c73||Save Data Transfer Tool|
|?||?||00000d9a||Donkey Kong Country™
Returns 3D: Trailer
|?||?||00000ea6||Etrian Odyssey IV|
|?||00000edf||00000ee0||Super Smash Bros. for Nintendo 3DS|
|?||00000f14||00000f1e||Phoenix Wright: Ace Attorney - Dual Destinies|
|?||00001007||00001005||Professor Layton vs Phoenix Wright: Ace Attorney|
|?||?||00001062||Nintendo Pocket Football Club|
|?||?||0000111c||Yoshi's New Island|
|000011c5||000011c5||000011c5||Pokémon Omega Ruby
Pokémon Alpha Sapphire
|?||?||000012ca||Mario vs. Donkey Kong: Tipping Stars|
|?||?||000014f2||Animal Crossing: Happy Home Designer|
|000014d1||000014d1||000014d1||Home Menu badge|
|?||?||00001632||Fullblox / Stretchmo|
|?||?||00001646||Pokémon Rumble World|
|0000165c||0000165c||0000165c||Home Menu saved theme layouts|
|?||?||000018fa||Phoenix Wright: Ace Attorney - Spirit of Justice|
|?||?||0000198f||Animal Crossing: New Leaf - Welcome amiibo|
|?||?||00001a05||Super Mario Maker|
|0xe0000000||Home Menu attempts to open this archive during boot, if FS:OpenArchive doesn't return an error Home Menu seems to then launch the System Transfer application. Home Menu doesn't actually use this archive at all except for checking whether it exists.|
|0xf0000001||NAND JPEG/MPO files and phtcache.bin from the camera application are stored here. This also contains UploadData.dat.|
|0xf0000002||NAND M4A files from the sound application are stored here|
|0xf0000009||Used for SpotPass content storage for notifications.|
|0xf000000b||Contains idb.dat, idbt.dat, gamecoin.dat, ubll.lst, CFL_DB.dat, and CFL_OldDB.dat. These files contain cleartext Miis and some data relating (including cached ICN data) to Play/Usage Records.|
|0xf000000c||Contains bashotorya.dat and bashotorya2.dat.|
|0xf000000d||Home Menu SpotPass content data storage.|
|0xf000000e||Contains versionlist.dat, used by Home Menu for the software update notification added with 7.0.0-13.|
|0x0||0x4||Magic number: 0x4F00|
|0x4||0x2||Total Play Coins|
|0x6||0x2||Total Play Coins obtained on the date stored below. When the below date does not match the current date, this field is reset to zero, then the date(and other fields) are updated. Once this value is >=10, no more Play Coins can be obtained until the current date changes.|
|0x8||0x4||Total step count at the time a new Play Coin was obtained.|
|0xC||0x4||Step count for the day the last Play Coin was obtained, for that day's step count(same as the step count displayed by home-menu when this file was updated).|
The above date stores the last time new Play Coin(s) were obtained. The contents of this file is updated by home-menu. PTM:GetTotalStepCount is not checked constantly, after home-menu boot this is only checked when waking from sleep-mode. Each time home-menu updates the contents of this file, home-menu will set the Play Coin total to 300 if it's higher than the 300 Play Coin limit.
Home Menu loads this file / opens this archive during startup. When accessing this file fails, like when the file/archive is corrupted(or at least on older system-versions), the result is a brick due to Home Menu using svcBreak. Yellows8 bricked a 3DS this way due to corruption via invalid FSFile:Write flush flags. When opening this extdata archive(0xf000000b) fails, Home Menu executes svcBreak.
List of blocked users.
Empty space is filled with 0xC-long sequences of 00 00 ... 07
- 3ds-save-tool - Extract/verifies extdata