Nintendo Switch Tool (NSTool)

General purpose reading/extraction tool for Nintendo Switch file formats.

Supported File Formats

• PartitionFs (PFS0) (.pfs0)
• Sha256PartitionFs (HFS0) (.hfs0)
• RomFs (.romfs)
• Nintendo Content Archive (.nca)
• Nintendo Submission Package (.nsp)
• NX GameCard Image (.xci)
• Meta (META) (.npdm)
• Nintendo Application Control Property (.nacp)
• Content Metadata (.cnmt)
• ES Certificate (.cert)
• ES Ticket (v2 only) (.tik)
• Nintendo Shared Object (NSO0) (.nso)
• Nintendo Relocatable Object (NRO0) (.nro)
• Initial Program Bundle (INI1) (.ini)
• Initial Program (KIP1) (.kip)

Usage

General usage

The default mode of NSTool is to show general information about a file.

To display general information the usage is as follows:

nstool some_file.bin

However not all information is shown in this mode; file-layout, key data and properties set to default values are omitted.

Alternative output modes

To output file-layout information, use the --showlayout option:

nstool --showlayout some_file.bin

To output key data generation and selection, use the --showkeys option:

nstool --showkeys some_file.bin

To output all information, enable the verbose output mode with the -v or --verbose option:

nstool -v some_file.bin

Specify File Type

NSTool will in most cases correctly identify the file type. However you can override this and manually specify the file type with the -t or --type option:

nstool -t cnmt some_file.bin

In that example cnmt was selected, NSTool would process the file as Content Metadata. See below for a list of supported file type codes:

Code	Description
gc, xci	NX GameCard Image
nsp	Nintendo Submission Package
pfs	PartitionFs
hfs	Sha256PartitionFs
romfs	RomFs
nca	Nintendo Content Archive
meta, npdm	Meta (.npdm)
cnmt	Content Metadata
nso	Nintendo Shared Object
nro	Nintendo Relocatable Object
ini	Initial Program Bundle
kip	Initial Program
nacp	Nintendo Application Control Property
cert	ES Certificate
tik	ES Ticket
aset, asset	Homebrew NRO Asset Binary

Validate Input File

Some file types have signatures/hashes/fields that can be validated by NSTool, but this mode isn't enabled by default.

To validate files with NSTool, enable the verify mode with the -y or --verify option:

nstool -y some_file.bin

See the below table for file types that support optional validation:

File Type	Validation	Comments
ES Certificate	Signature	If certificate is part of a certificate chain it will validate it as part of that chain. Root signed certificates are verified with user supplied Root public key.
ES Ticket	Signature	If the user specifies a certificate chain with --cert option, the ticket will be verified against that certificate chain.
NX GameCard Image	XCI Header Signature, HFS0 Hashes	XCI header signature is verified with user supplied XCI Header public key.
META	AccessControlInfo fields, AccessControlInfoDesc signature	AccessControlInfo fields are validated against the AccessControlInfoDesc. AccessControlInfoDesc signature is verfied with the appropriate user supplied ACID public key.
NCA	Header Signature[0], Header Signature[1]	Header Signature[0] is verified with the appropriate user supplied NCA Header public key. Header Signature[1] is verified only in Program titles, by retrieving the with public key from the AccessControlInfoDesc stored in the code partition.

• As of Nintendo Switch Firmware 9.0.0, Nintendo retroactively added key generations for some public keys, including NCA Header and ACID public keys, so the various generations for these public keys will have to be supplied by the user.
• As of NSTool v1.6.0 the public key(s) for Root Certificate, XCI Header, ACID and NCA Header are built-in, and will be used if the user does not supply the public key in a key file.

DevKit Mode

Files generated for Production use different (for the most part) encryption/signing keys than files generated for Development. NSTool will select Production encryption/signing keys by default. When handling files intended for developer consoles (e.g. systemupdaters, devtools, test builds, etc), you should enable developer mode with the -d, --dev option:

nstool -d some_file.bin

Extract Files

Some file types have an internal file system. This can be displayed and extracted.

To display the file system tree, use the file tree option --fstree:

nstool --fstree some_file.bin

To extract the file system, use the extract option -x, --extract. Which has four modes.

1. Extract the entire file system.

This extracts the contents of the entire file system to ./extract_dir/. extract_dir will be created if it doesn't exist.

nstool -x ./extract_dir/ some_file.bin

2. Extract a sub directory.

This extracts the contents of /a/sub/directory/ to ./extract_dir/. extract_dir will be created if it doesn't exist.

nstool -x /a/sub/directory/ ./extract_dir/ some_file.bin

3. Extract a specific file, preserving the original name.

This extracts /path/to/a/file.bin to ./extract_dir/file.bin.

nstool -x /path/to/a/file.bin ./extract_dir/ some_file.bin

4. Extract a specific file with a custom name.

This extracts /path/to/a/file.bin to ./extract_dir/different_name.bin.

nstool -x /path/to/a/file.bin ./extract_dir/different_name.bin some_file.bin

Supported File Types

• PartitionFs
• Sha256PartitionFs
• RomFs (including RomFs embedded in Homebrew NRO)
• NCA
• NSP
• XCI

NCA Patches

Nintendo distributes game patches/updates in the style of a diff to keep file sizes down. This means extracting game patches requires the base version of the game to be able to process patch data. Typically this is only done for the Program NCA.

If basegame_v0.nca is the base Program NCA, and gamepatch_v13219.nca is the patch Program NCA, simply specify the base NCA using the base NCA option --basenca when processing the patch NCA.

nstool --basenca ./basegame_v0.nca -x ./patchdata gamepatch_v13219.nca

In the above example the patch NCA is being extracted to ./patchdata

Encrypted Files

Some Nintendo Switch files are partially or completely encrypted. These require the user to supply the encryption keys to NSTool so that it can process them.

See SWITCH_KEYS.md for more info.

External Keys

NSTool doesn't embed any keys that are copyright protected. However keys can be imported via various keyset files.

See SWITCH_KEYS.md for more info.

Building

See BUILDING.md.