For the content of the NCA FS which can be [[Filesystem_services|mounted]], see [[NCA_Content_FS|here]].

For the format of the actual NCA, see [[NCA_Format|here]].

= Metadata file =
This is the file that ends in <code>".cnmt{.nca}"</code> or <code>"meta0.ncd"</code>. This seems to replace the TMD format.

There's at least 9 different filenames used for ".cnmt":
* "Application_{lower-case hex titleID}.cnmt"
* "Patch_{lower-case hex titleID}.cnmt"
* "AddOnContent_{lower-case hex titleID}.cnmt"
* "SystemUpdate_{hex titleID}.cnmt"
* "SystemData_{lower-case hex titleID}.cnmt"
* "SystemProgram_{lower-case hex titleID}.cnmt"
* "BootImagePackage_{lower-case hex titleID}.cnmt"
* "BootImagePackageSafe_{lower-case hex titleID}.cnmt"
* "Delta_{lower-case hex titleID}.cnmt"

It starts with a header:
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 8
| Title ID
|-
| 0x8
| 4
| u32 [[Title_list|title-version]]
|-
| 0xC
| 1
| Type (see [[NCM_services#Title_Types|Title Types]])
|-
| 0xD
| 1
|
|-
| 0xE
| 2
| Offset to table relative to the end of this 0x20-byte header.
|-
| 0x10
| 2
| Number of content entries
|-
| 0x12
| 2
| Number of meta entries
|-
| 0x14
| 12
|
|}

With SystemUpdate, the 4-bytes at offset 0xE are zero, with the entry-count field located at offset 0x12 instead(header size is the same).

An optional header can follow, depending on the title type.

At the end of the file following the entries is a 0x20-byte block, presumably a hash.

With Patch-format, there's additional data after the end of the entries specified in the header and before the ending hash.

== Application header ==
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x20
| 8
| Patch Title ID
|-
| 0x28
| 8
| Minimum system version
|}

== Patch header ==
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x20
| 8
| Original title ID
|-
| 0x28
| 8
| Minimum system version
|}

== Add-on content header ==
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x20
| 8
| Application title ID
|-
| 0x28
| 8
| Minimum application version
|}

== Content records ==

Each entry is 0x38 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 32
| Hash
|-
| 0x20
| 16
| NcaId [same as first 16-bytes of hash]
|-
| 0x30
| 6
| Size, same as the output from [[Content_Manager_services#GetEntrySize]].
|-
| 0x36
| 1
| Type (0=Meta, 1=Program, 2=Data, 3=Control, 4=[[Internet_Browser|HtmlDocument]], 5=[[Internet_Browser|LegalInformation]], 6=[[NCA_Format|DeltaFragment]])
|-
| 0x37
| 1
|
|}

== Meta records ==

Each entry is 0x10 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 8
| Title ID
|-
| 0x8
| 4
| Title version
|-
| 0xC
| 1
| Type (see [[NCM_services#Title_Types|Title Types]])
|-
| 0xD
| 1
| ? bit0 set = don't install?
|-
| 0xE
| 2
| Unused?
|}

This is used for SystemUpdate, see here: [[Content_Manager_services#GetUpdateTitleList]].

== Extended data ==

Patch-type cnmt files include an extended data section.

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 4
| Number of previous cnmt entries.
|-
| 0x4
| 4
| Number of previous delta entries.
|-
| 0x8
| 4
| Number of delta info entries.
|-
| 0xC
| 4
| Number of delta application info entries.
|-
| 0x10
| 4
| Number of previous content entries.
|-
| 0x14
| 4
| Number of delta content entries.
|-
| 0x18
| 4
| Unused?
|-
| 0x1C
| 0x38*X
| Previous cnmt entries
|-
|
| 0x28*X
| Previous delta entries
|-
|
| 0x28*X
| Delta info entries
|-
|
| 0x34*X
| Delta application info entries
|-
|
| 0x18*X
| Previous content entries
|-
|
| 0x38*X
| Delta content entries. (Standard content records)
|-
|
| 4
| Unknown
|-
|
| 4
| Unknown
|-
|
| 4
| Unknown
|-
|}

== Previous cnmt records ==

Each entry is 0x38 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 8
| Title ID
|-
| 0x8
| 4
| Title version
|-
| 0xC
| 1
| Type (see [[NCM_services#Title_Types|Title Types]])
|-
| 0xD
| 3
| Unused?
|-
| 0x10
| 32
| Hash
|-
| 0x30
| 2
| Unknown
|-
| 0x32
| 2
| Unused?
|-
| 0x34
| 4
| Unused?
|-
|}

This contains information on previous metadata files.

== Previous delta records ==

Each entry is 0x28 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 8
| Old title ID
|-
| 0x8
| 8
| New title ID
|-
| 0x10
| 4
| Old title version
|-
| 0x14
| 4
| New title version
|-
| 0x18
| 8
| Size
|-
| 0x20
| 8
| Unused?
|-
|}

This contains information on previous delta patches.

== Delta info records ==

Each entry is 0x28 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 8
| Old title ID
|-
| 0x8
| 8
| New title ID
|-
| 0x10
| 4
| Old title version
|-
| 0x14
| 4
| New title version
|-
| 0x18
| 8
| Some sort of index?
|-
| 0x20
| 8
| Some sort of index?
|-
|}

This contains information on the current delta patch.

== Delta application info records ==

Each entry is 0x34 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 16
| Old NcaId
|-
| 0x10
| 16
| New NcaId
|-
| 0x20
| 6
| Old size
|-
| 0x26
| 2
| Upper 2 bytes of the new size
|-
| 0x28
| 4
| Lower 4 bytes of the new size
|-
| 0x2C
| 2
| Unknown
|-
| 0x2E
| 1
| Type (see [[NCM_services#Title_Types|Title Types]])
|-
| 0x2F
| 1
| ? bit0 set = don't install?
|-
| 0x30
| 4
| Unused?
|-
|}

This contains information on how to apply deltas to the previous patch.

== Previous content records ==

Each entry is 0x18 bytes:

{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 16
| NcaId
|-
| 0x10
| 6
| Size
|-
| 0x16
| 1
| Type (see [[NCM_services#Title_Types|Title Types]])
|-
| 0x17
| 1
|
|-
|}

This contains information on previous title content from earlier patches.

Talk:NSO0

2017-08-08T09:55:41Z

Hiccup:

Has anyone made a tool for decompressing the "main" file in the exefs? --[[User:Hiccup|Hiccup]] ([[User talk:Hiccup|talk]]) 09:10, 7 August 2017 (CDT)
* https://gist.github.com/SciresM/62715cfb5d06648ee46bc4622d2725e5 --[[User:SciresM|SciresM]] ([[User talk:SciresM|talk]]) 10:07, 7 August 2017 (CDT)
:Thanks. Can I share this link, or would you prefer I didn't? --[[User:Hiccup|Hiccup]] ([[User talk:Hiccup|talk]]) 06:43, 8 August 2017 (CDT)
::Also, which python version is this for? --[[User:Hiccup|Hiccup]] ([[User talk:Hiccup|talk]]) 06:55, 8 August 2017 (CDT)

2017-06-05T06:58:57Z

Hiccup: split each element into columns

{| class=wikitable
! Title-id || Description || Region || Type
|-
| 01000320000CC000 || 1-2 Switch || ALL || Game
|-
| 0100EE6002B48000 || ACA Neo Geo Fatal Fury || ALL || VC
|-
| 0100CB2001DB8000 || ACA Neo Geo Garou: Mark of the Wolves || ALL || VC
|-
| 0100BA8001DC6000 || ACA Neo Geo Metal Slug 3 || ALL || VC
|-
| 01003A5001DBA000 || ACA Neo Geo Over Top || ALL || VC
|-
| 0100EB2001DCC000 || ACA Neo Geo The King of Fighters '94 || ALL || VC
|-
| 0100B42001DB4000 || ACA Neo Geo The King of Fighters '98 || ALL || VC
|-
| 01002E70032E8000 || ACA Neo Geo Turf Masters || ALL || VC
|-
| 0100CEF001DC0000 || ACA Neo Geo Waku Waku 7 || ALL || VC
|-
| 01009D4001DC4000 || ACA Neo Geo World Heroes Perfect || ALL || VC
|-
| 0100C5E003B40000 || ARMS Global Testpunch || ALL || Timed Demo
|-
| 010025B002E92000 || Blaster Master Zero || ALL || Demo
|-
| 0100225000FEE000 || Blaster Master Zero || ALL || Demo
|-
| 01001FA0034E2000 || Dark Witch Music Episode: Rudymical || ALL || Game
|-
| 0100E67003A86000 || Disgaea 5 Complete || ALL || Game
|-
| 0100930002EAA000 || Dragon Quest Heroes 1 & 2 || USA || Game
|-
| 0100F12002FC8000 || Everyone Party! Spelunker || JPN || Game
|-
| 01009510001CA000 || FAST RMX || JPN || Game
|-
| 01006740034F6000 || Just Dance 2017 || USA || Game
|-
| 010085300314E000 || Kamiko || USA || Game
|-
| 0100152000022000 || Mario Kart 8 Deluxe || ? || Game
|-
| 01006BD001E06000 || Minecraft: Nintendo Switch Edition || ? || Game
|-
| 010031F002B66000 || Mr. Shifty || ? || Game
|-
| 010002900294A000 || NBA Playgrounds || ? || Game
|-
| 01004C200100E000 || New Frontier Days: Founding Pioneers || ? || Game
|-
| 0100902001014000 || Othello || ? || Game
|-
| 01000DC003740000 || Puyo Puyo Tetris || ? || Game
|-
| 01004B10031BE000 || Puyo Puyo Tetris || ? || Game
|-
| 010000A00218E000 || Splatoon 2 Global Testfire || ALL || Timed Demo
|}