The following is a list of known file formats used by the 3DS.
Applications ( any executable code )
.CCI - 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.
.CXI - Executable image. Similar to above. The difference is CXI applications are installed onto [thus ran from] NAND.
.CIA - (CTR Importable Archive) It is the application compiled into an archive, ready to be installed to a designated location. A .CIA file can be extracted to install applications to the, CTR NAND, TWL NAND (part of the NAND used by DSi applications), and the SD card.
.CSU - System Update. Format varies slightly with revisions.
.CFA - CTR File Archive - Externalized ROM-FS. CXI data and ROMFS data can be separated into a list of external files instead of compiled into just 1 CXI image (Normally not used). Lib states this is similar to a CIA, a little like an archive of a CIA. Fortunately lib has some info on this format. CFA files are basically multiple packed CIAs. CFAs are used when the CCI file includes the child device distributed with download play.
.NSA - Archive used by several of the communication protocols in the 3DS.
.RSF - Descriptive data used when outputting a CCI/CXI file. Specifies options such as: title, save type, and so on.
.AXF - Pre-assembled ARM code. before being linked into a CCI/CXI format. They're practically ARM specific ELF files.
.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.
.CIP - (CTR Initial Process)
.BCWAV - CTR waveform file format
.CBMD - CTR binary banner model. Archive file before being made into a CTR banner for games or other applications.
The 3DS filesystem requires absolute paths. It can handle either short (8.3) and long (255 char maximum) file names.
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
Pages in category "File formats"
The following 30 pages are in this category, out of 30 total.