Nintendo Switch Brew

XCI: Difference between revisions

← Older editNewer edit →
No edit summary
Line 1: Line 1:
Known internally as "XCI" (NX Card Image), this is the format used for storing the contents of a Nintendo Switch Gamecard.  
This is the format used for storing the contents of a Nintendo Switch Gamecard.


= Gamecard Header =
= Structure =
This header is 0x200 bytes and is located at offset 0 in the Gamecard.
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x1000
| [[#CardKeyArea]]
|-
| 0x1000
| 0x200
| [[#CardHeader]]
|-
| 0x1200
| 0x6E00
| ReservedArea
|-
| 0x8000
| 0x8000
| [[#CertArea]]
|-
| 0x10000
| Variable
| [[#NormalArea]]
|-
| Variable
| Variable
| [[#RomArea]]
|-
| Invalid
| Invalid
| BackupArea
|}
 
== CardKeyArea ==
This region cannot be read directly once written to the Gamecard. Therefore, it is hidden away during read/write operations on the raw Gamecard data.
 
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x200
| [[#InitialData]]
|-
| 0x200
| 0xD00
| [[#TitleKeyArea]]
|-
| 0xF00
| 0x100
| Reserved
|}
 
=== InitialData ===
This region is used for challenge–response authentication when changing to the Gamecard's secure mode.
 
[[Filesystem_services|FS]] calculates a SHA-256 hash over the whole 0x200 bytes and compares it with the hash stored at offset 0x160 in the [[#CardHeader]].
 
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x8
| Package ID from [[#CardHeader]] at offset 0x110
|-
| 0x8
| 0x8
| Empty
|-
| 0x10
| 0x10
| Challenge–response authentication data
|-
| 0x20
| 0x10
| Challenge–response authentication MAC
|-
| 0x30
| 0xC
| Challenge–response authentication Nonce
|-
| 0x3C
| 0x1C4
| Reserved (must be empty)
|}
 
=== TitleKeyArea ===
This region is stored encrypted and contains the title keys used by the [[#InitialData]].
 
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x8
| TitleKey1
|-
| 0x8
| 0x8
| TitleKey2
|-
| 0x10
| 0xCF0
| Reserved
|}


== CardHeader ==
{| class="wikitable" border="1"
{| class="wikitable" border="1"
|-
|-
Line 16: Line 130:
| 0x100
| 0x100
| 0x4
| 0x4
| Magicnum "HEAD"
| MagicCode ("HEAD")
|-
|-
| 0x104
| 0x104
| 0x4
| 0x4
| Secure Area Start Address (in Media Units which are 0x200 bytes)
| RomAreaStartPageAddress (in Gamecard page units, which are 0x200 bytes)
|-
|-
| 0x108
| 0x108
| 0x4
| 0x4
| Backup Area Start Address (always 0xFFFFFFFF)
| BackupAreaStartPageAddress (always 0xFFFFFFFF)
|-
|-
| 0x10C
| 0x10C
| 0x1
| 0x1
| TitleKeyDec Index (high nibble) and KEK Index (low nibble)
| TitleKeyDecIndex (high nibble) and KekIndex (low nibble)
|-
|-
| 0x10D
| 0x10D
| 0x1
| 0x1
| [[#Gamecard Size|Gamecard Size]]
| [[#RomSize]]
|-
|-
| 0x10E
| 0x10E
| 0x1
| 0x1
| Gamecard Header Version
| CardHeaderVersion
|-
|-
| 0x10F
| 0x10F
| 0x1
| 0x1
| [[#Gamecard Flags|Gamecard Flags]]
| [[#Flags]]
|-
|-
| 0x110
| 0x110
| 0x8
| 0x8
| Package ID (used for challenge–response authentication)
| PackageId (used for challenge–response authentication)
|-
|-
| 0x118
| 0x118
| 0x8
| 0x8
| Valid Data End Address (in Media Units which are 0x200 bytes)
| ValidDataEndAddress (in Gamecard page units, which are 0x200 bytes)
|-
|-
| 0x120
| 0x120
| 0x10
| 0x10
| Gamecard Info IV (reversed)
| Iv (reversed)
|-
|-
| 0x130
| 0x130
| 0x8
| 0x8
| HFS0 partition offset
| PartitionFsHeaderAddress
|-
|-
| 0x138
| 0x138
| 0x8
| 0x8
| HFS0 header size
| PartitionFsHeaderSize
|-
|-
| 0x140
| 0x140
| 0x20
| 0x20
| SHA-256 hash of the [[#HFS0 Header|HFS0 Header]]
| PartitionFsHeaderHash (SHA-256 hash of the [[#PartitionFsHeader]])
|-
|-
| 0x160
| 0x160
| 0x20
| 0x20
| SHA-256 hash of the [[#Initial Data|Initial Data]]
| InitialDataHash (SHA-256 hash of the [[#InitialData]])
|-
|-
| 0x180
| 0x180
| 0x4
| 0x4
| Security Mode (0x01 = T1, 0x02 = T2)
| SelSec (0x01 = T1, 0x02 = T2)
|-
|-
| 0x184
| 0x184
| 0x4
| 0x4
| T1 Key Index (always 2)
| SelT1Key (always 2)
|-
|-
| 0x188
| 0x188
| 0x4
| 0x4
| Key Index (always 0)
| SelKey (always 0)
|-
|-
| 0x18C
| 0x18C
| 0x4
| 0x4
| Normal Area End Address (in Media Units which are 0x200 bytes)
| LimArea (in Gamecard page units, which are 0x200 bytes)
|-
|-
| 0x190
| 0x190
| 0x70
| 0x70
| [[#Gamecard Info|Gamecard Info]] (AES-128-CBC encrypted)
| [[#CardInfo]] ( encrypted)
|}
 
=== CardInfo ===
This region is stored encrypted (AES-128-CBC).
 
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x8
| FwVersion (0x00 = Development, 0x01 = Retail, [4.0.0+] 0x02 = Retail, [11.0.0+] 0x04 = Retail)
|-
| 0x8
| 0x4
| AccCtrl1 (0x00A10011 = 25MHz access, 0x00A10010 = 50MHz access)
|-
| 0xC
| 0x4
| Wait1TimeRead (always 0x1388)
|-
| 0x10
| 0x4
| Wait2TimeRead (always 0)
|-
| 0x14
| 0x4
| Wait1TimeWrite (always 0)
|-
| 0x18
| 0x4
| Wait2TimeWrite (always 0)
|-
| 0x1C
| 0x4
| FwMode (the current SdkAddonVersion)
|-
| 0x20
| 0x4
| UppVersion
|-
| 0x24
| 0x1
| [9.0.0+] CompatibilityType (0x00 = Normal, 0x01 = Terra)
|-
| 0x25
| 0x3
| Empty
|-
| 0x28
| 0x8
| UppHash (SHA-256 hash of the [[#UpdatePartition]])
|-
| 0x30
| 0x8
| UppId (always 0x0100000000000816)
|-
| 0x38
| 0x38
| Empty
|}
|}


== Gamecard Size ==
=== RomSize ===
[[Filesystem_services|FS]] retrieves this data as [[Filesystem_services#GameCardSize|GameCardSize]].
[[Filesystem_services|FS]] retrieves this data as [[Filesystem_services#GameCardSize|GameCardSize]].


Line 118: Line 294:
|}
|}


== Gamecard Flags ==
=== Flags ===
[[Filesystem_services|FS]] retrieves this data as [[Filesystem_services#GameCardAttribute|GameCardAttribute]].
[[Filesystem_services|FS]] retrieves this data as [[Filesystem_services#GameCardAttribute|GameCardAttribute]].


Line 142: Line 318:
|}
|}


== Gamecard Info ==
== CertArea ==
When decrypted, this 0x70 byte region is as follows:
This is the Gamecard's unique certificate.
 
{| class="wikitable" border="1"
|-
! Offset
! Size
! Description
|-
| 0x0
| 0x8
| Firmware Version (0x00 = Development, 0x01 = Retail, [4.0.0+] 0x02 = Retail, [11.0.0+] 0x04 = Retail)
|-
| 0x8
| 0x4
| Access Control (0x00A10011 = 25MHz access, 0x00A10010 = 50MHz access)
|-
| 0xC
| 0x4
| Read Time Wait1 (always 0x1388)
|-
| 0x10
| 0x4
| Read Time Wait2 (always 0)
|-
| 0x14
| 0x4
| Write Time Wait1 (always 0)
|-
| 0x18
| 0x4
| Write Time Wait2 (always 0)
|-
| 0x1C
| 0x4
| Firmware Mode
|-
| 0x20
| 0x4
| CUP Version
|-
| 0x24
| 0x1
| [9.0.0+] Compatibility Type (0x00 = Normal, 0x01 = Terra)
|-
| 0x25
| 0x3
| Empty
|-
| 0x28
| 0x8
| Update Partition Hash
|-
| 0x30
| 0x8
| CUP ID (always 0x0100000000000816, which is the title-listing data archive's title ID)
|-
| 0x38
| 0x38
| Empty
|}
 
= Gamecard Certificate =
This is the Gamecard's unique certificate and is located at offset 0x7000.


[[Filesystem_services|FS]] retrieves this data with [[Filesystem_services#GetGameCardDeviceCertificate|GetGameCardDeviceCertificate]].
[[Filesystem_services|FS]] retrieves this data with [[Filesystem_services#GetGameCardDeviceCertificate|GetGameCardDeviceCertificate]].
Line 221: Line 335:
| 0x100
| 0x100
| 0x4
| 0x4
| Magicnum "CERT"
| MagicCode ("CERT")
|-
|-
| 0x104
| 0x104
| 0x4
| 0x4
| Empty
| Version
|-
|-
| 0x108
| 0x108
| 0x1
| 0x1
| KEK Index
| KekIndex
|-
|-
| 0x109
| 0x109
| 0x7
| 0x7
| Empty
| Reserved
|-
|-
| 0x110
| 0x110
| 0x10
| 0x10
| Device ID
| DeviceId
|-
|-
| 0x120
| 0x120
| 0x10
| 0x10
| Unknown
| Iv
|-
|-
| 0x130
| 0x130
| 0xD0
| 0xD0
| Encrypted data
| Data (encrypted)
|-
| 0x200
| 0x7E00
| Reserved
|}
|}


The data between the Gamecard Certificate and the start of the HFS0 region is all 0xFF, except for a few carts that have been found, inwhich it is 0x00.
== NormalArea ==
 
This region contains all non-secure partitions of the Gamecard file system.
= Initial Data =
This data is used for challenge–response authentication when changing to the Gamecard's secure mode.
 
[[Filesystem_services|FS]] calculates a SHA-256 hash over the whole 0x200 bytes and compares it with the hash stored at offset 0x160 in the [[#Gamecard Header|Gamecard Header]].


{| class="wikitable" border="1"
{| class="wikitable" border="1"
Line 261: Line 375:
! Description
! Description
|-
|-
| 0x0
| Variable
| 0x8
| Variable
| Package ID from [[#Gamecard Header|Gamecard Header]] at offset 0x110
| [[#PartitionFsHeader|RootPartitionHeader]]
|-
| Variable
| Variable
| [[#PartitionFsHeader|UpdatePartitionHeader]]
|-
| Variable
| Variable
| [[#UpdatePartition]]
|-
| Variable
| Variable
| [4.0.0+] [[#PartitionFsHeader|LogoPartitionHeader]]
|-
| Variable
| Variable
| [4.0.0+] [[#LogoPartition]]
|-
|-
| 0x8
| Variable
| 0x8
| Variable
| Empty
| [[#PartitionFsHeader|NormalPartitionHeader]]
|-
|-
| 0x10
| Variable
| 0x10
| Variable
| Challenge–response authentication data
| [[#NormalPartition]]
|}
 
=== UpdatePartition ===
This partition contains .cnmt.nca + .nca files for the entire system update required to play the game. Launch day carts contain a full copy of 1.0 ncas, newer carts contain newer sysupdate NCAs etc.
 
=== NormalPartition ===
This partition contains the .cnmt.nca and the game icondata nca. This is presumably for future compatibility so that if a future update changes the cryptographic protocol for the secure partition. Game icon data can still be shown in the home menu on old firmwares.
 
[4.0.0+] This partition is now empty.
 
=== LogoPartition ===
[4.0.0+] This partition now contains the contents of the [[#NormalPartition]].
 
== RomArea ==
This region contains all secure partitions of the Gamecard file system.
 
{| class="wikitable" border="1"
|-
|-
| 0x20
! Offset
| 0x10
! Size
| Challenge–response authentication MAC
! Description
|-
|-
| 0x30
| Variable
| 0xC
| Variable
| Challenge–response authentication Nonce
| [[#PartitionFsHeader|SecurePartitionHeader]]
|-
|-
| 0x3C
| Variable
| 0x1C4
| Variable
| Reserved (must be empty)
| [[#SecurePartition]]
|}
|}


= HFS0 =
=== SecurePartition ===
This partition contains an identical copy of the .cnmt.nca and game icondata nca, as well as all other ncas required for the game.
 
== PartitionFs ==
This is the Gamecard file system which starts with magicnum "HFS0".
This is the Gamecard file system which starts with magicnum "HFS0".


== Header ==
=== PartitionFsHeader ===
The "SHA-256 File System" or "HFS0" starts at offset 0xF000 in the Gamecard. The first 0x200 bytes act as a global header and represent the root partition which points to the other partitions ("normal", "logo", "update" and "secure).
The "SHA-256 File System" or "HFS0" starts at offset 0x10000 in the Gamecard. The first 0x200 bytes act as a global header and represent the root partition which points to the other partitions ("normal", "logo", "update" and "secure).


A hash for this header is stored at offset 0x140 in the [[#Gamecard Header|Gamecard Header]].
A hash for this header is stored at offset 0x140 in the [[#CardHeader]].
 
== File System ==
The actual file system is as follows (also valid for the root partition):


{| class="wikitable" border="1"
{| class="wikitable" border="1"
Line 305: Line 452:
| 0x0
| 0x0
| 0x4
| 0x4
| Magicnum "HFS0"
| MagicCode ("HFS0")
|-
|-
| 0x4
| 0x4
| 0x4
| 0x4
| Number of files
| FileCount
|-
|-
| 0x8
| 0x8
| 0x4
| 0x4
| Size of the string table
| StringTableSize
|-
|-
| 0xC
| 0xC
| 0x4
| 0x4
| Zero/Reserved
| Reserved
|-
|-
| 0x10
| 0x10
| X
| X
| File Entry Table
| [[#FileEntryTable]]
|-
|-
| 0x10 + X
| 0x10 + X
| Y
| Y
| String Table
| StringTable
|-
|-
| 0x10 + X + Y
| 0x10 + X + Y
| Z
| Z
| Raw File Data
| RawFileData
|}
|}


Where File Entry Table consists of Number of Files FileEntries:
==== FileEntryTable ====
 
{| class="wikitable" border="1"
{| class="wikitable" border="1"
|-
|-
Line 366: Line 512:


The string table is 00-padded to align the start of raw filedata with a sector/media unit boundary (usually?).
The string table is 00-padded to align the start of raw filedata with a sector/media unit boundary (usually?).
= Cartridge Layout =
Observed gamecards contain three partitions: "update", "normal", and "secure".
The update partition (Gamecard partition 0 for fsp-srv cmd 31) contains .cnmt.nca + .nca files for the entire system update required to play the game. Launch day carts contain a full copy of 1.0 ncas, newer carts contain newer sysupdate NCAs etc.
The normal partition contains the .cnmt.nca and the game icondata nca. This is presumably for future compatibility so that if a future update changes the cryptographic protocol for the secure partition, Game icon data can still be shown in the home menu on old firmwares.
The secure partition contains an identical copy of the .cnmt.nca and game icondata nca, as well as all other ncas required for the game.
The entire rest of the Gamecard after the secure partition ends is all FF padding.
[4.0.0+] The "normal" partition is now empty and a new partition "logo" was added.
A partition "boot" got added with exact same content than "logo".
Retrieved from "https://switchbrew.org/wiki/XCI"