Flash Filesystem
NAND structure
The Switch's eMMC storage features a large user area, two smaller boot partitions and a replay-protected memory block which is unused (no authentication key is programmed).
All official partition names come from SystemInitializer.
Boot Partitions
Boot Partition 0 (0 of 1)
The official name for this partition is "BootPartition1Root" and it has Bis Partition ID == 0.
| Offset | Size | Description |
|---|---|---|
| 0x000000 | 0x4000 | Normal Firmware BCT from Title 0100000000000819 |
| 0x004000 | 0x4000 | SafeMode Firmware BCT from Title 010000000000081A |
| 0x008000 | 0x4000 | Normal Firmware BCT from Title 0100000000000819 (backup) |
| 0x00C000 | 0x4000 | SafeMode Firmware BCT from Title 010000000000081A (backup) |
| 0x010000 | 0xEC000 | 59 additional BCTs, normally unused/empty on retail systems. |
| 0x0FC000 | 0x4000 | System Update Control area |
| 0x100000 | 0x40000 | Normal Firmware package1 from Title 0100000000000819 |
| 0x140000 | 0x40000 | Normal Firmware package1 from Title 0100000000000819 (backup) |
| 0x180000 | 0x4000 | Keyblob area |
| 0x184000 | 0x200 | [2.0.0+] NAND Patrol area |
Boot Partition 1 (1 of 1)
The official name for this partition is "BootPartition2Root" and it has Bis Partition ID == 10.
| Offset | Size | Description |
|---|---|---|
| 0x000000 | 0x40000 | SafeMode Firmware package1 from Title 010000000000081A |
| 0x040000 | 0x40000 | SafeMode Firmware package1 from Title 010000000000081A (backup) |
| 0x080000 | 0x40000 | Reserved |
| 0x0C0000 | 0x40000 | Reserved |
System Update Control
The 0x4000 bytes at offset 0xFC000 are used by NS and boot for keeping track of the status of a system update. This area is used by the ISystemUpdateControl commands ApplyDownloadedUpdate, ApplyCardUpdate and ApplyReceivedUpdate.
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x1 | BootImages status. Set to 1 by NS during a system update and cleared by boot after restarting. |
| 0x1 | 0x1 | BootImagesSafe status. Set to 1 by NS during a system update and cleared by boot after restarting. |
Keyblob
Starting at offset 0x180000 is an array of 0x200-byte entries, for a total of 32 keyblobs. Each one is unique compared to the others and they are all console unique. This is officially known as the "EKS" (encryption key source) area.
From each 0x200-byte entry only the first 0xB0 bytes effectively form the keyblob as below.
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x10 | Keyblob AES-CMAC over the next 0xA0 bytes (safe against timing attacks) |
| 0x10 | 0x10 | Keyblob AES CTR |
| 0x20 | 0x90 | Keyblob encrypted payload |
| 0xB0 | 0x150 | Unused, all-zero. |
The active bootloader's version (offset 0x2330 in the BCT) acts as an index (version-1) to control which keyblob should be installed into the system.
NS uses this during system updates to install the keyblob into the customer data section in BCTs (offset 0x450).
Boot also uses this index for repairing corrupt sectors.
The currently active keyblob is officially known as "SecureInfo".
NAND Patrol
The 0x200 bytes at offset 0x184000 are used by FS for keeping track of NAND patrolling.
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x20 | HMAC-SHA-256 over the next 0x1E0 bytes |
| 0x20 | 0x4 | Last patrolled NAND block's offset |
| 0x24 | 0x4 | NAND patrol count |
| 0x28 | 0x1D8 | Unused, all-zero. |
User Partitions
| Partition name | Partition type GUID | Offset | Size | Bis Partition ID | Encrypted | Description |
|---|---|---|---|---|---|---|
| N/A | 0x0 | 20 | No | GPT header, Bis-storage also allows raw access to the entire NAND eMMC sectors starting at sector0. The official name for this partition is "UserDataRoot". | ||
| PRODINFO | {98109E25-64E2-4C95-8A77-414916F5BCEB} | 0x00004400 | 0x003FBC00 | 27 | Yes (Bis key 0) | "CAL0" raw partition containing set:cal data. The official name for this partition is "CalibrationBinary". |
| PRODINFOF | {F3056AEC-5449-494C-9F2C-5FDCB75B6E6E} | 0x00400000 | 0x00400000 | 28 | Yes (Bis key 0) | FAT12 filesystem, additional calibration. The official name for this partition is "CalibrationFile". |
| BCPKG2-1-Normal-Main | {5365DE36-911B-4BB4-8FF9-AA1EBCD73990} | 0x00800000 | 0x00800000 | 21 | No | Raw partition where the first 0x4000 bytes (usually empty) contain the BootConfig and the remaining space contains the package2 image from Title 0100000000000819 by default. With the exFAT update installed, the package2 image is switched to the one from Title 010000000000081B. The official name for this partition is "BootConfigAndPackage2Part1". |
| BCPKG2-2-Normal-Sub | {8455717B-BD2B-4162-8454-91695218FC38} | 0x01000000 | 0x00800000 | 22 | No | Backup partition for BCPKG2-1-Normal-Main. The official name for this partition is "BootConfigAndPackage2Part2". |
| BCPKG2-3-SafeMode-Main | {8ED6C9A6-9C48-490B-BBEB-001D17A4C0F7} | 0x01800000 | 0x00800000 | 23 | No | Raw partition where the first 0x4000 bytes (usually empty) contain the BootConfig and the remaining space contains the package2 image from Title 010000000000081A by default. On [4.0.0+] and with the exFAT update installed, the package2 image is switched to the one from Title 010000000000081C. The official name for this partition is "BootConfigAndPackage2Part3". |
| BCPKG2-4-SafeMode-Sub | {5E99751C-56C9-47CC-AA30-B65039888917} | 0x02000000 | 0x00800000 | 24 | No | Backup partition for BCPKG2-3-SafeMode-Main. The official name for this partition is "BootConfigAndPackage2Part4". |
| BCPKG2-5-Repair-Main | {C447D9A2-24B7-468A-98C8-595CD077165A} | 0x02800000 | 0x00800000 | 25 | No | Installed at the factory, never written afterwards on retail. In one case this is identical to normal 1.0.0 package2, except this has encrypted data at the end padded for 0x1000-byte alignment. The official name for this partition is "BootConfigAndPackage2Part5". |
| BCPKG2-6-Repair-Sub | {9586E1A1-3AA2-4C90-91B3-2F4A5195B4D2} | 0x03000000 | 0x00800000 | 26 | No | Backup partition for BCPKG2-5-Repair-Main. The official name for this partition is "BootConfigAndPackage2Part6". |
| SAFE | {A44F9F6B-4ED3-441F-A34A-56AAA136BC6A} | 0x03800000 | 0x04000000 | 29 | Yes (Bis key 1) | FAT32 filesystem. The official name for this partition is "SafeMode". |
| SYSTEM | {ACB0CDF0-4F72-432D-AA0D-5388C733B224} | 0x07800000 | 0xA0000000 | 31, 32 and 33 | Yes (Bis key 2) | FAT32 filesystem. The official names for these partitions are "System", "SystemProperEncryption" and "SystemProperPartition". |
| USER | {2B777F63-E842-47AF-94C4-25A7F18B2280} | 0xA7800000 | 0x680000000 | 30 | Yes (Bis key 3) | FAT32 filesystem. |
| 0x747BFFE00 | 0x200 | No | This is the backup GPT header specified by the main GPT header. This is also the last sector readable with Bis-storage paritionID 20. |
If the client process lacks the relevant permission for any of the above partition IDs, error 0x2EE202 is returned.
NCAs stored in NAND are raw, identical to the data readable with NCM_services#ReadContentIdFile.
The filenames for saveimages is just "<lower-case hex u64 saveID>". SYSTEM-partition saveIDs are specified by FS commands, while USER-partition saveIDs are determined by FS-module internally. The high u32 of the saveID is normally either 0x00000000 or 0x80000000.
Encrypted partitions use AES-XTS using the same non-standard tweak (tweak[0] = sectorIdx[MSB] .. tweak[15] = sectorIdx[LSB], if using 32bit sectorIdx that means tweak[0]..tweak[11] are 0, with tweak[12]..tweak[15] containing big-endian sectorIdx) as other Nintendo AES-XTS code, initial_sector = 0, and sector size 0x4000. All encrypted partitions use console unique keydata.
SYSTEM
SYSTEM ├── PRF2SAFE.RCV ├── Contents │ ├── registered │ │ └── ... NCA │ └── placehld │ └── ... NCA ├── save │ └── ... └── saveMeta └── ... (empty?)
The saves stored under this partition are only for system-titles / etc.
USER
USER ├── PRF2SAFE.RCV ├── Album (Same layout as SD) ├── Contents │ ├── registered │ │ └── ... NCA │ └── placehld │ └── ... NCA ├── save │ └── ... ├── saveMeta │ └── ... └── temp
The saves for all non-system applications, regardless of where the application is located(storageID), is stored here. Each user account which has savedata has a separate saveimage. Save-common for an application is presumably a separate saveimage too. Every saveimage here is only for applications.
SAFE
SAFE ├── PRF2SAFE.RCV ├── Contents │ ├── registered │ │ └── ... NCA (nothing installed?) │ └── placehld │ └── ... NCA └── save ├── 8000000000000000 └── 8000000000000120
On a v2.1 system with MountBis, the only thing under here is "PRF2SAFE.RCV".
SystemSaveData
This is a listing of known SystemSaveData and what titles they correspond to.
| SystemSaveDataId | Owner | Mount | SaveDataFlags | Notes |
|---|---|---|---|---|
| 0x8000000000000000 | fs | saveDataIxrDb:/, saveDataIxrDbSf:/, saveDataIxrDbPr:/, saveDataIxrDbSd:/ | Contains imkvdb.arc and "lastPublishedId". | |
| 0x8000000000000010 | account | account:/ | 0xC | Account database. |
| 0x8000000000000011 | account | idgen:/ | 0x1 | |
| 0x8000000000000020 | nfc | data:/ | 0x0 | NFC data and backups. |
| 0x8000000000000030 | ns | mii:/ | 0x4 | Mii database. |
| 0x8000000000000031 | ns | mii:/ | Mii test mode database. | |
| 0x8000000000000040 | ns | apprecdb:/ | 0x0 | |
| 0x8000000000000041 | ns | nsaccache:/ | 0x4 | Home menu icondata/lru list for recently played games. |
| 0x8000000000000043 | ns | ns_appman:/ | 0x0 | |
| 0x8000000000000044 | ns | ns_sysup:/ | 0x0 | Content update context. |
| 0x8000000000000045 | ns | [7.0.0+] lrdb:/ ([1.0.0-6.2.0] vmdb:/) | 0x4 | Required Version List storage. Also contained Version List storage before 7.0.0. |
| 0x8000000000000046 | ns | dtlman:/ | 0x0 | |
| 0x8000000000000047 | ns | ns_exfat:/ | 0x1 | |
| 0x8000000000000048 | ns | ns_systemseed:/ | 0x1 | |
| 0x8000000000000049 | ns | ns_ssversion:/ | 0x3 | Safe System version. |
| 0x800000000000004A | ns | ns_rightsid:/ | 0x0 | List of RightsIDs with NCA IDs for corresponding Program title. |
| 0x8000000000000050 | settings | SystemSettings:/ | 0x8 | |
| 0x8000000000000051 | settings | FwdbgSettingsS:/ | 0x3 | [4.0.0+] Only used if in development mode. |
| 0x8000000000000052 | settings | PrivateSettings:/ | 0x1 | |
| 0x8000000000000053 | settings | DeviceSettings:/ | 0x3 | |
| 0x8000000000000054 | settings | ApplnSettings:/ | 0x4 | |
| 0x8000000000000060 | ssl | SslSave:/ | 0x0 | |
| 0x8000000000000070 | nim | nim_sys:/ | 0x0 | |
| 0x8000000000000071 | nim | nim_net:/ | 0x0 | |
| 0x8000000000000072 | nim | nim_tmp:/ | 0x0 | |
| 0x8000000000000073 | nim | nim_dac:/ | 0x0 | |
| 0x8000000000000074 | nim | nim_delta:/ | 0x0 | |
| 0x8000000000000075 | nim | nim_vac:/ | ||
| 0x8000000000000076 | nim | nim_local:/ | 0x0 | |
| 0x8000000000000077 | nim | nim_lsys:/ | 0x0 | |
| 0x8000000000000078 | nim | nim_eca_dbg:/ | ||
| 0x8000000000000080 | friends | friends:/ | Per-user savedata. | |
| 0x8000000000000081 | friends | friends-sys:/ | ||
| 0x8000000000000082 | friends | friends-image:/ | ||
| 0x8000000000000090 | bcat | news:/ | 0x0 | Actual news msgpack archives. |
| 0x8000000000000091 | bcat | news-sys:/ | 0x0 | News metadata, tasklist, history, database, required system version, etc. |
| 0x8000000000000092 | bcat | news-dl:/ | 0x0 | Storage for newly(?) downloaded news list/data. |
| 0x80000000000000A0 | bcat | prepo-sys:/ | 0x8 | Play Report system information. |
| 0x80000000000000A1 | bcat | prepo:/ | 0x8 | Play Report msgpack archives. |
| 0x80000000000000A2 | bcat | prepo-ap:/ | 0x8 | Play Report msgpack archives of EventId "application_execution_history". |
| 0x80000000000000B0 | bsdsockets | nsdsave:/ | Socket configuration saved data. | |
| 0x80000000000000C1 | bcat | bcat-sys:/ | 0x0 | |
| 0x80000000000000C2 | bcat | bcat-dl:/ | 0x0 | |
| 0x80000000000000D1 | erpt | save:/ | 0x4 | Contains "/journal" report listing + actual crash reports ("/%08x-%04x-%04x-%02x%02x-%04x%08x"), which are serialized via MsgPack. |
| 0x80000000000000E0 | es | escertificate:/ | 0x0 | |
| 0x80000000000000E1 | es | escommon:/ | 0x0 | |
| 0x80000000000000E2 | es | espersonalized:/ | 0x0 | |
| 0x80000000000000E3 | es | esmetarecord:/ | 0x0 | |
| 0x80000000000000E4 | es | eselicense:/ | 0x0 | |
| 0x80000000000000F0 | ns | pdm:/ | 0x0 | Play Data log. Per-user savedata. |
| 0x8000000000000100 | pctl | pctlss:/ | 0x0 | Parental Control settings. |
| 0x8000000000000110 | npns | npns_save:/ | 0x4 | Push notifications persistent storage. |
| 0x8000000000000120 | ncm | 0x3 | meta/imkvdb.arc for system partition. Cache of data extracted from the CNMT for installed firmware titles (including 816). | |
| 0x8000000000000121 | ncm | 0x0 | meta/imkvdb.arc for user partition. Cache of data extracted from the CNMT for installed game, update, and DLC titles. | |
| 0x8000000000000122 | ncm | 0x0 | ||
| 0x8000000000000130 | migration | state:/ | 0x4 | |
| 0x8000000000000131 | migration | context:/ | ||
| 0x8000000000000132 | migration | sd_state:/ | 0x4 | |
| 0x8000000000000133 | migration | sd_context:/ | 0x4 | |
| 0x8000000000000140 | capsrv | TM:/ | 0x0 | |
| 0x8000000000000150 | olsc | olsc:/ | 0x0 | |
| 0x8000000000000151 | olsc | olsc:/ | ||
| 0x8000000000000152 | olsc | olsc:/ | ||
| 0x8000000000000153 | olsc | repair:/ | 0x0 | |
| 0x8000000000000180 | sdb | [7.0.0+] vmdb:/ | 0x0 | Version list. |
| 0x8000000000000190 | glue | 0x8 | ||
| 0x8000000000000200 | bcat | mnpp_m:/ | 0xC | |
| 0x8000000000000210 | account | dauth:/ | 0x0 | |
| 0x8000000000000220 | erpt | sprof:/ | 0x1 | |
| 0x8000000000001010 | qlaunch | save:/ | 0x0 | Contains "savedata.dat". |
| 0x8000000000001011 | qlaunch | group:/ | Contains "savedata.dat". | |
| 0x8000000000001020 | swkbd | save:/ | Contains "savedata.dat". | |
| 0x8000000000001021 | swkbd | save:/ | 0x0 | Contains "savedata.dat". |
| 0x8000000000001030 | auth | save:/ | 0x0 | Contains "savedata.dat". |
| 0x8000000000001040 | miiEdit | save:/ | 0x0 | Contains "savedata.dat". |
| 0x8000000000001050 | miiEdit | MiiImage:/ | 0x4 | Contains "database.dat". |
| 0x8000000000001060 | LibAppletShop | savecommon:/ | 0x8 | |
| 0x8000000000001061 | LibAppletShop | saveuser:/ | Per-user savedata. | |
| 0x8000000000001070 | LibAppletWeb | savecommon:/ | 0x8 | |
| 0x8000000000001071 | LibAppletWeb | saveuser:/ | Per-user savedata. | |
| 0x8000000000001080 | LibAppletOff | savecommon:/ | Unused. | |
| 0x8000000000001081 | LibAppletOff | saveuser:/ | Unused. | |
| 0x8000000000001090 | LibAppletLns | savecommon:/ | 0x8 | |
| 0x8000000000001091 | LibAppletLns | saveuser:/ | Per-user savedata. | |
| 0x80000000000010A0 | LibAppletAuth | savecommon:/ | Unused. | |
| 0x80000000000010A1 | LibAppletAuth | saveuser:/ | Unused. | |
| 0x80000000000010B0 | playerSelect | save:/ | 0x0 | Contains "savedata.dat". |
| 0x80000000000010C0 | myPage | save:/ | Contains "savedata.dat". | |
| 0x80000000000010E1 | qlaunch | mig:/ | Contains "savedata.dat". | |
| 0x8000000000001100 | qlaunch | news:/ | 0x0 | Contains "savedata.dat". |
| 0x8000000000002000 | DevMenu | |||
| 0x8000000000002020 | ns | ns_confidential:/ | ||
| 0x8000000000010002 | bcat | Delivery cache storage for application 010099F00D810000 | ||
| 0x8000000000010003 | bcat | 0x0 | Delivery cache storage for application 0100000000001033 | |
| 0x8000000000010004 | bcat | 0x0 | Delivery cache storage for application 0100000000001034 | |
| 0x8000000000010005 | bcat | 0x3 | Delivery cache storage for application 010000000000102E | |
| 0x8000000000010006 | bcat | 0x0 | Delivery cache storage for application 010000000000102F | |
| 0x8000000000010007 | bcat | 0x0 | Delivery cache storage for application 0100000000001007 |