Category:File formats

The following is a list of known file formats used by the 3DS.

NCCH

.CXI - CTR Executable image - Are either packaged into a CCI/CSU for running off a cartridge, or packaged into a CIA for installing to the SDMC or NAND.

.CFA - CTR File Archive - Externalized Rom-FS. This is non-executable specialisation of the NCCH container format. Generally used in conjunction with an executable specialisation of the NCCH container format (CXI).

.APP - The per-console encrypted form of a NCCH file, used with installed titles, like eShop and CDN downloads.

NCSD

.CCI - CTR Cart image - Burned into a ROM (or loaded by official debugging hardware). These are also the actual format of ROM dumps, and the response of read requests between a 3DS and a cartridge. This is simply a NCCH container, with a maximum of 8 NCCHs.

.CSU - CTR System Update - Format varies slightly with revisions.

Descriptor File Formats

.BSF - Descriptive data used when outputting ICN/BNR files. The .XBSF format used by CiTRUS is based on the concept of .BSF.

.RSF - Descriptive data used when outputting a CCI/CXI file. Specifies options such as: title, save type, and so on.

.DESC - Descriptive data used when outputting a CCI/CXI file. Like the .RSF format, but more complex (more complex in the options which it can specify).

ExeFS Related File Formats

.AXF - Pre-assembled ARM code. Before being linked into the ExeFS '.code' format. They're practically ARM specific ELF files. The Plain Region found in the CXI is also obtain from this file.

.BNR - Simply contains a .CBMD and a .BCWAV, in that order with padding in between the two files to make sure the .BCWAV is aligned to 0x10 bytes. It contains nothing else.

• .CBMD - CTR binary banner model - Archive file before being made into a CTR banner for games or other applications.

• .BCWAV - CTR waveform file format

.ICN - Contains icons, names and flags for an application

• .CTPK - CTR Texture Package

Other File Formats

.CIA - CTR Importable Archive - This format allows the installation titles to the 3DS. CIA files can compile a CXI for installation to either the SDMC or CTR NAND. CIA files can also compile .SRL files (format for DS(i) executable images) for installation to the TWL NAND of the 3DS.

.TMD - Title Metadata - The format is used with installed/installable titles. Notably they are found in .CIA files (plain text), on the SD card (encrypted), NAND and on Nintendo's CDN (plain text).

.CDI - CTR Development Image - CDI files are system processes which other types of applications depend on for access to various other lower level functions. CDI are normally the same titles as listed in a CXI header's dependency list, they are just compiled to a different format. The difference is that CDI is used for a different (test) environment. They're loaded into hardware debugger's memory, along with the 2 cores in order to execute.

.NSA - Archive used by several of the communication protocols in the 3DS.

.CIP - (CTR Initial Process)

.CTX - When beginning eShop app downloads, this file is created. Later this file is written with actual data. When the download is completed, the file is deleted from SD card.(This might then be moved to NAND) This is encrypted with a per-console key. It contains a signed cert followed by unknown data. It is only 1.50kbyte. Here is an example.[1]

.MPO - Multi-Picture Object Format - Document describing the file format used in mpo files: http://www.cipa.jp/english/hyoujunka/kikaku/pdf/DC-007_E.pdf

Filesystem

The 3DS filesystem requires absolute paths. It can handle either short (8.3) and long (255 char maximum) file names.