CNMT

This is the metadata file that ends in ".cnmt{.nca}" or "meta0.ncd". 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"

Header

Offset	Size	Description
0x0	0x8	Title ID
0x8	0x4	Version
0xC	0x1	Meta Type
0xD	0x1	Unused
0xE	0x2	Extended Header Size
0x10	0x2	Content Count
0x12	0x2	Content Meta Count
0x14	0x1	Attributes (0=None, 1=IncludesExFatDriver, 2=Rebootless)
0x15	0x3	Unused
0x18	0x4	Required Download System Version
0x1C	0x4	Unused

SystemUpdate Extended Header

Offset	Size	Description
0x0	0x4	Extended Header Size

Application Extended Header

Offset	Size	Description
0x0	0x8	Patch ID
0x8	0x4	Required System Version

Patch Extended Header

Offset	Size	Description
0x0	0x8	Application ID
0x8	0x4	Required System Version
0xC	0x4	Extended Data Size
0x10	0x8	Unused

AddOnContent Extended Header

Offset	Size	Description
0x0	0x8	Application ID
0x8	0x4	Required Application Version
0xC	0x4	Unused

Delta Extended Header

Offset	Size	Description
0x0	0x8	Application ID
0x8	0x4	Extended Data Size
0xC	0x4	Unused

Content records

Offset	Size	Description
0x0	0x20	Hash
0x20	0x10	Content ID
0x30	0x6	Size
0x36	0x1	Title Type (0=Meta, 1=Program, 2=Data, 3=Control, 4=HtmlDocument, 5=LegalInformation, 6=DeltaFragment)
0x37	0x1	Id Offset

Meta records

Offset	Size	Description
0x0	0x8	Title ID
0x8	0x4	Version
0xC	0x1	Meta Type
0xD	0x1	Attributes (0=None, 1=IncludesExFatDriver, 2=Rebootless)
0xE	0x2	Unused

This is used for SystemUpdate, see here: NCM_services#ReadEntryMetaRecords.

Extended data

Patch-type cnmt files include an extended data section.

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:

Offset	Size	Description
0x0	8	Title ID
0x8	4	Title version
0xC	1	Type (see 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:

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:

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:

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 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:

Offset	Size	Description
0x0	16	NcaId
0x10	6	Size
0x16	1	Type (see Title Types)
0x17	1

This contains information on previous title content from earlier patches.