Filesystem services

fsp-ldr

This is "nn::fssrv::sf::IFileSystemProxyForLoader".

Cmd	Name	Arguments	Notes
0	OpenCodeFileSystem	u64 TitleId + X descriptor #ContentPath	Returns an #IFileSystem.
1	IsArchivedProgram	u64 ProcessId	Returns a bool (1 if the process id's #ContentPath ends in ".nca").
2	[4.0.0+] SetCurrentProcess	PID descriptor

fsp-pr

This is "nn::fssrv::sf::IProgramRegistry".

Cmd	Name	Notes
0	#RegisterProgram
1	#UnregisterProgram
2	[4.0.0+] SetCurrentProcess
256	#SetEnabledProgramVerification

RegisterProgram

Takes a storageID, a pid, a titleID, a 0x1C type-A buffer for the FS Access Header, and a 0x2C type-A buffer for the FS Access Control

Final FS permissions are stored as (ACI0_perms & ACID_perms). Will panic(svcBreak) when buffer sizes from ipc-rawdata are invalid.

UnregisterProgram

Takes a pid. Removes registered FS permissions for that PID.

SetEnabledProgramVerification

Seems to sets a global flag to inputval & 1.

When the flag is zero, it will set ret=0 instead of ret={error} when verifying the fixed-key NPDM ACID signature fails. This also skips verifying the NCA Header signature using the ACID key. Note that if verifying the fixed-key ACID signature is successful, and verifying the ACID-key NCA header signature fails, it will throw an error and abort.

fsp-srv

This is "nn::fssrv::sf::IFileSystemProxy".

Cmd	Name
0	[1.0.0] #OpenFileSystem
1	#SetCurrentProcess
2	OpenDataFileSystemByCurrentProcess
7	[2.0.0+] #OpenFileSystemWithPatch
8	[2.0.0+] #OpenFileSystemWithId
9	[3.0.0+] OpenDataFileSystemByApplicationId
11	#OpenBisFileSystem
12	#OpenBisStorage
13	InvalidateBisCache
17	OpenHostFileSystem
18	OpenSdCardFileSystem
19	[2.0.0+] FormatSdCardFileSystem
21	#DeleteSaveDataFileSystem
22	#CreateSaveDataFileSystem
23	#CreateSaveDataFileSystemBySystemSaveDataId
24	RegisterSaveDataFileSystemAtomicDeletion
25	[2.0.0+] DeleteSaveDataFileSystemBySaveDataSpaceId
26	[2.0.0+] FormatSdCardDryRun
27	[2.0.0+] IsExFatSupported
28	[4.0.0+] DeleteSaveDataFileSystemBySaveDataAttribute
30	#OpenGameCardStorage
31	#OpenGameCardFileSystem
32	[3.0.0+] ExtendSaveDataFileSystem
33	[5.0.0+] DeleteCacheStorage
34	[5.0.0+] GetCacheStorageSize
35	[6.0.0+] CreateSaveDataFileSystemByHashSalt (Unofficial name, takes a total of 0xB0-bytes of input, no output)
51	#OpenSaveDataFileSystem
52	#OpenSaveDataFileSystemBySystemSaveDataId
53	[2.0.0+] OpenReadOnlySaveDataFileSystem
57	[3.0.0+] #ReadSaveDataFileSystemExtraDataBySaveDataSpaceId
58	#ReadSaveDataFileSystemExtraData
59	[2.0.0+] WriteSaveDataFileSystemExtraData
60	#OpenSaveDataInfoReader
61	#OpenSaveDataInfoReaderBySaveDataSpaceId
62	[5.0.0+] OpenCacheStorageList
64	[5.0.0+] OpenSaveDataInternalStorageFileSystem
65	[5.0.0+] UpdateSaveDataMacForDebug
66	[5.0.0+] WriteSaveDataFileSystemExtraData2
67	[6.0.0+] FindSaveDataWithFilter (Takes a total of 0x50-bytes of input, returns 8-bytes of output, and a type-0x6 output buffer)
68	[6.0.0+] OpenSaveDataInfoReaderBySaveDataFilter (Unofficial name, takes a total of 0x50-bytes of input, returns an #ISaveDataInfoReader)
80	OpenSaveDataMetaFile
81	[4.0.0+] OpenSaveDataTransferManager (No input, returns an #ISaveDataTransferManager)
82	[5.0.0+] OpenSaveDataTransferManagerVersion2 (No input, returns an #ISaveDataTransferManagerWithDivision)
83	[6.0.0+] OpenSaveDataTransferProhibiterForCloudBackUp (Takes an input u64, returns an #ISaveDataTransferProhibiter)
84	[6.0.0+] ListApplicationAccessibleSaveDataOwnerId (Takes a total of 0x10-bytes of input, returns 4-bytes of output, and a type-0x6 output buffer)
100	OpenImageDirectoryFileSystem
110	#OpenContentStorageFileSystem
120	[6.0.0+] OpenCloudBackupWorkStorageFileSystem (Takes 4-bytes of input, returns an #IFileSystem)
130	[7.0.0+] OpenCustomStorageFileSystem (Takes 4-bytes of input, returns an #IFileSystem)
200	OpenDataStorageByCurrentProcess
201	[3.0.0+] OpenDataStorageByProgramId
202	#OpenDataStorageByDataId
203	OpenPatchDataStorageByCurrentProcess
204	[7.0.0+] ? (Takes an input u8, returns an #IFileSystem)
205	[7.0.0+] ? (Takes an input u8, returns an #IStorage)
400	#OpenDeviceOperator
500	#OpenSdCardDetectionEventNotifier
501	#OpenGameCardDetectionEventNotifier
510	[5.0.0+] OpenSystemDataUpdateEventNotifier
511	[5.0.0+] NotifySystemDataUpdateEvent
520	[6.0.0+] SimulateGameCardDetectionEvent (Takes a total of 0xC-bytes of input, no output)
600	[1.0.0-3.0.2] SetCurrentPosixTime
601	QuerySaveDataTotalSize
602	#VerifySaveDataFileSystem
603	CorruptSaveDataFileSystem
604	CreatePaddingFile
605	DeleteAllPaddingFiles
606	[2.0.0+] GetRightsId
607	[2.0.0+] RegisterExternalKey
608	[2.0.0+] UnregisterAllExternalKey
609	[2.0.0+] GetRightsIdByPath
610	[3.0.0+] GetRightsIdAndKeyGenerationByPath
611	[4.0.0+] SetCurrentPosixTimeWithTimeDifference
612	[4.0.0+] GetFreeSpaceSizeForSaveData
613	[4.0.0+] VerifySaveDataFileSystemBySaveDataSpaceId
614	[4.0.0+] CorruptSaveDataFileSystemBySaveDataSpaceId
615	[5.0.0+] QuerySaveDataInternalStorageTotalSize
616	[6.0.0+] #GetSaveDataCommitId
620	[2.0.0+] #SetSdCardEncryptionSeed
630	[4.0.0+] SetSdCardAccessibility
631	[4.0.0+] IsSdCardAccessible
640	[4.0.0+] IsSignedSystemPartitionOnSdCardValid
700	[5.0.0+] OpenAccessFailureResolver
701	[5.0.0+] GetAccessFailureDetectionEvent
702	[5.0.0+] IsAccessFailureDetected
710	[5.0.0+] ResolveAccessFailure
720	[5.0.0+] AbandonAccessFailure
800	[2.0.0+] GetAndClearFileSystemProxyErrorInfo
1000	SetBisRootForHost
1001	SetSaveDataSize
1002	SetSaveDataRootPath
1003	DisableAutoSaveDataCreation
1004	#SetGlobalAccessLogMode
1005	#GetGlobalAccessLogMode
1006	#OutputAccessLogToSdCard
1007	[4.0.0+] RegisterUpdatePartition
1008	[4.0.0+] OpenRegisteredUpdatePartition
1009	[4.0.0+] GetAndClearMemoryReportInfo
1010	[5.1.0+] SetDataStorageRedirectTarget
1100	[4.0.0+] OverrideSaveDataTransferTokenSignVerificationKey
1110	[6.0.0+] CorruptSaveDataFileSystemBySaveDataSpaceId2
1200	[6.0.0+] OpenMultiCommitManager (No input, returns an output #IMultiCommitManager)

Permissions

Every time permissions are checked, the process registration #fsp-pr is loaded using the session processID. The permission data is populated with data from the NPDM.

If the processID is <= 6 (which happens only for built-in sysmodules), it will use a hardcoded registration data. The default mask in this case is 0x8000000000000000.

Note that the functions check whether or not at least one bit is set in the mask. This means that, you don't need to set 0xFFFFFFFFFFFFFFFF to get all permissions: it suffices to set 0x8000000000000000.

If the code were to request an invalid input type, panic. But this never happens.

RwPermissions

Type(s)	Mask	Name	Value	Used by
0x0	0x8000000000000801	CanMountLogo	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x1	0x8000000000000801	CanMountContentMeta	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x2	0x8000000000000801	CanMountContentControl	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x3	0x8000000000000801	CanMountContentManual	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x4	0x8000000000000801	CanMountContentData	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x5	0x8000000000000801	CanMountApplicationPackage	1	#OpenFileSystem, #OpenFileSystemWithPatch, #OpenFileSystemWithId
0x6	0x8000000000000000	CanMountSaveDataStorage	3
0x7	0x8000000000000800	CanMountContentStorage	3	#OpenContentStorageFileSystem
0x8	0x8000000000001000	CanMountImageAndVideoStorage	3	#OpenImageDirectoryFileSystem
0x9	0x8000000200000000 ([1.0.0-5.1.0] 0x8000000000000084)	CanMountCloudBackupWorkStorage	3	OpenCloudBackupWorkStorageFileSystem
0xA	0x8000000000000084 ([1.0.0-5.1.0] 0x8000000000000080)	CanMountBisCalibrationFile	3	#OpenBisFileSystem
0xB	0x8000000000000080 ([1.0.0-5.1.0] 0x8000000000008080)	CanMountBisSafeMode	3	#OpenBisFileSystem
0xC	0x8000000000008080	CanMountBisUser	3	#OpenBisFileSystem
0xD	0x8000000000008080 ([1.0.0-5.1.0] 0x8000000000000080)	CanMountBisSystem	3	#OpenBisFileSystem
0xE	0x8000000000000080 ([1.0.0-2.3.0] 0xC000000000200000)	CanMountBisSystemProperEncryption	3	#OpenBisFileSystem
0xF	0x8000000000000080 ([3.0.0-5.1.0] 0xC000000000200000) ([1.0.0-2.3.0] 0x8000000000000010)	CanMountBisSystemProperPartition	3	#OpenBisFileSystem
0x10	0xC000000000200000 ([3.0.0-5.1.0] 0x8000000000000010) ([1.0.0-2.3.0] 0x8000000000040020)	CanMountSdCard	3	#OpenSdCardFileSystem
0x11	0x8000000000000010 ([3.0.0-5.1.0] 0x8000000000040020) ([1.0.0-2.3.0] 0x8000000000000028)	CanMountGameCard	3	#OpenGameCardFileSystem
0x12	0x8000000000040020 ([3.0.0-5.1.0] 0x8000000000000028) ([1.0.0-2.3.0] 0x8000000000000020)	CanMountDeviceSaveData	3	#OpenSaveDataFileSystem
0x13	0x8000000000000028 ([1.0.0-5.1.0] 0x8000000000000020)	CanMountSystemSaveData	3	#OpenSaveDataFileSystemBySystemSaveDataId
0x14	0x8000000000000020 ([1.0.0-2.3.0] 0x8000000000010082)	CanMountOthersSaveData	3	#OpenSaveDataFileSystem
0x15	0x8000000000000020 ([3.0.0-5.1.0] 0x8000000000010082) ([1.0.0-2.3.0] 0x8000000000010080)	CanMountOthersSystemSaveData	3	#OpenSaveDataFileSystemBySystemSaveDataId
0x16	0x8000000000010082 ([1.0.0-5.1.0] 0x8000000000010080)	CanOpenBisPartitionBootPartition1Root	3	#OpenBisStorage
0x17	0x8000000000010080 ([3.0.0-5.1.0] 0x8000000000000080) ([1.0.0-2.3.0] 0x8000000000010080)	CanOpenBisPartitionBootPartition2Root	3	#OpenBisStorage
0x18	0x8000000000000080 ([1.0.0-5.1.0] 0x8000000000010080)	CanOpenBisPartitionUserDataRoot	3	#OpenBisStorage
0x19	0x8000000000010080	CanOpenBisPartitionBootConfigAndPackage2Part1	3	#OpenBisStorage
0x1A	0x8000000000010080	CanOpenBisPartitionBootConfigAndPackage2Part2	3	#OpenBisStorage
0x1B	0x8000000000010080	CanOpenBisPartitionBootConfigAndPackage2Part3	3	#OpenBisStorage
0x1C	0x8000000000010080	CanOpenBisPartitionBootConfigAndPackage2Part4	3	#OpenBisStorage
0x1D	0x8000000000010080 ([1.0.0-2.3.0] 0x8000000000000084)	CanOpenBisPartitionBootConfigAndPackage2Part5	3	#OpenBisStorage
0x1E	0x8000000000010080 ([1.0.0-5.1.0] 0x8000000000000084)	CanOpenBisPartitionBootConfigAndPackage2Part6	3	#OpenBisStorage
0x1F	0x8000000000000084 ([1.0.0-2.3.0] 0x8000000000000080)	CanOpenBisPartitionCalibrationBinary	3	#OpenBisStorage
0x20	0x8000000000000084 ([1.0.0-5.1.0] 0x8000000000000080)	CanOpenBisPartitionCalibrationFile	3	#OpenBisStorage
0x21	0x8000000000000080	CanOpenBisPartitionSafeMode	3	#OpenBisStorage
0x22	0x8000000000000080	CanOpenBisPartitionUser	3	#OpenBisStorage
0x23	0x8000000000000080 ([1.0.0-2.3.0] 0xC000000000200000)	CanOpenBisPartitionSystem	3	#OpenBisStorage
0x24	0x8000000000000080 ([1.0.0-2.3.0] 0x8000000000000100)	CanOpenBisPartitionSystemProperEncryption	3	#OpenBisStorage
0x25	0x8000000000000080 ([3.0.0-5.1.0] 0xC000000000200000) ([1.0.0-2.3.0] 0x8000000000100008)	CanOpenBisPartitionSystemProperPartition	3	#OpenBisStorage
0x26	0xC000000000200000 ([3.0.0-5.1.0] 0x8000000000000100) ([1.0.0-2.3.0] 0xC000000000400000)	CanOpenSdCardStorage
[3.0.0+] 0x27	0x8000000000000100 ([1.0.0-5.1.0] 0x8000000000100008)	CanOpenGameCardStorage	3	#OpenGameCardStorage, #EraseGameCard (bit1), #WriteToGameCard (bit1), #GetGameCardErrorInfo (bit1), #EraseAndWriteParamDirectly (bit1), #ReadParamDirectly (bit1), #ForceEraseGameCard (bit1)
[3.0.0+] 0x28	0x8000000000100008 ([1.0.0-5.1.0] 0xC000000000400000)	CanMountSystemDataPrivate	1	#OpenFileSystem, #OpenDataStorageByDataId
[4.0.0+] 0x29	0xC000000000400000 ([1.0.0-5.1.0] 0x8000000000010000)	CanMountHost	3	#OpenHostFileSystem
[5.0.0+] 0x2A	0x8000000000010000 ([1.0.0-5.1.0] 0x8000000000000000)	CanMountRegisteredUpdatePartition	1	#OpenRegisteredUpdatePartition
[6.0.0+] 0x2B	0x8000000000000000	CanOpenSaveDataInternalStorage	3	#OpenSaveDataInternalStorageFileSystem

BoolPermissions

Type(s)	Mask	Name	Used by
0x0	0x8000000000000080	CanInvalidateBisCache	#InvalidateBisCache
0x1	0x8000000000000080	CanEraseMmc	#EraseMmc
0x2	0x8000000000000010	CanGetGameCardDeviceCertificate	#GetGameCardDeviceCertificate
0x3	0x8000000000000010	CanGetGameCardIdSet	#GetGameCardIdSet
0x4	0x8000000000000200	CanFinalizeGameCardDriver	#FinalizeGameCardDriver
0x5	0x8000000000000200	CanGetGameCardAsicInfo	#GetGameCardAsicInfo
0x6	0x8000000000002020	CanCreateSaveData	#CreateSaveDataFileSystem
0x7	0x8000000000000060	CanDeleteSaveData	#DeleteSaveDataFileSystem, #RegisterSaveDataFileSystemAtomicDeletion
0x8	0x8000000000000028	CanCreateSystemSaveData	#CreateSaveDataFileSystemBySystemSaveDataId
0x9	0x8000000000000020	CanCreateOthersSystemSaveData	#CreateSaveDataFileSystemBySystemSaveDataId
0xA	0x8000000000004028	CanDeleteSystemSaveData	#DeleteSaveDataFileSystem, #RegisterSaveDataFileSystemAtomicDeletion
0xB	0x8000000000000060	CanOpenSaveDataInfoReader	#OpenSaveDataInfoReaderBySaveDataSpaceId, #OpenSaveDataInfoReader
0xC	0x8000000000004020	CanOpenSaveDataInfoReaderForSystem	#OpenSaveDataInfoReaderBySaveDataSpaceId, #OpenSaveDataInfoReader
0xD	0x8000000000000040 ([1.0.0-5.1.0] 0x8000000000020000)		OpenSaveDataInfoReaderBySaveDataFilter
0xE	0x8000000000020000 ([1.0.0-5.1.0] 0x8000000000000400)	CanOpenSaveDataMetaFile	#OpenSaveDataMetaFile
0xF	0x8000000000000400 ([1.0.0-5.1.0] 0x8000000000004060)	CanSetCurrentPosixTime	#SetCurrentPosixTime, #SetCurrentPosixTimeWithTimeDifference
0x10	0x8000000000004060 ([1.0.0-5.1.0] 0x8000000000080000)	CanReadSaveDataFileSystemExtraData	#ReadSaveDataFileSystemExtraData
0x11	0x8000000000080000	CanSetGlobalAccessLogMode	#SetGlobalAccessMode
0x12	0x8000000000080000 ([1.0.0-5.1.0] Invalid)	CanSetSpeedEmulationMode	#SetSpeedEmulationMode
0x13	Invalid ([1.0.0-5.1.0] 0xC000000000800000)
0x14	0xC000000000800000 ([1.0.0-5.1.0] 0xC000000001000000)	CanFillBis	#CreatePaddingFile, #DeleteAllPaddingFiles
0x15	0xC000000001000000 ([5.0.0-5.1.0] 0x8000000001000060) ([1.0.0-4.1.0] 0xC000000002000000)	CanCorruptSaveData	#CorruptSaveDataFileSystem, #CorruptSaveDataFileSystemBySaveDataSpaceId
[2.0.0+] 0x16	0x8000000001000060 ([5.0.0-5.1.0] 0x8000000000000060) ([1.0.0-4.1.0] 0x8000000004000000)	CanCorruptSystemSaveData	#CorruptSaveDataFileSystem, #CorruptSaveDataFileSystemBySaveDataSpaceId
[2.0.0+] 0x17	0x8000000000000060 ([5.0.0-5.1.0] 0xC000000002000000) ([1.0.0-4.1.0] 0x8000000008000000)	CanVerifySaveData	#VerifySaveDataFileSystem, #VerifySaveDataFileSystemBySaveDataSpaceId
[2.0.0+] 0x18	0xC000000002000000 ([5.0.0-5.1.0] 0x8000000004000000) ([1.0.0-4.1.0] 0x8000000010000000)	CanDebugSaveData	#CreateSaveDataFileSystem, #OpenSaveDataFileSystem, #SetSaveDataRootPath
[2.0.0+] 0x19	0x8000000004000000 ([5.0.0-5.1.0] 0x8000000008000000) ([1.0.0-4.1.0] 0x8000000000000800)	CanFormatSdCard	#FormatSdCardFileSystem
[2.0.0+] 0x1A	0x8000000008000000 ([5.0.0-5.1.0] 0x8000000010000000) ([1.0.0-4.1.0] 0x8000000000004020)	CanGetRightsId	#GetRightsId, #GetRightsIdAndKeyGenerationByPath, #GetRightsIdByPath
[3.0.0+] 0x1B	0x8000000010000000 ([5.0.0-5.1.0] 0x8000000000000800) ([1.0.0-4.1.0] 0x8000000000002020)	CanRegisterExternalKey	#RegisterExternalKey, #UnregisterAllExternalKey
[3.0.0+] 0x1C	0x8000000000000800 ([5.0.0-5.1.0] 0x8000000000004020) ([1.0.0-4.1.0] 0x8000000000000028)	CanSetEncryptionSeed	#SetSdCardEncryptionSeed
[4.0.0+] 0x1D	0x8000000000000020 ([5.0.0-5.1.0] 0x8000000000000000) ([1.0.0-4.1.0] 0x8000000020000000)	SaveDataExtraData_Write0	#WriteSaveDataFileSystemExtraData, #WriteSaveDataFileSystemExtraData2
[4.0.0+] 0x1E	0x8000000000004020 ([5.0.0-5.1.0] 0x8000000000002020) ([1.0.0-4.1.0] 0x8000000040000000)	CanWriteSaveDataFileSystemExtraDataFlags	#WriteSaveDataFileSystemExtraData, #WriteSaveDataFileSystemExtraData2
[4.0.0+] 0x1F	0x8000000000000020 ([5.0.0-5.1.0] 0x8000000000000028) ([1.0.0-4.1.0] 0x8000000000000000)	SaveDataExtraData_Write1	#WriteSaveDataFileSystemExtraData, #WriteSaveDataFileSystemExtraData2
[4.0.0+] 0x20	0x8000000000000000 ([5.0.0-5.1.0] 0x8000000020000000) ([1.0.0-4.1.0] 0x8000000000000000)	CanWriteSaveDataFileSystemExtraDataAll	#WriteSaveDataFileSystemExtraData, #WriteSaveDataFileSystemExtraData2
[5.0.0+] 0x21	0x8000000000002020 ([1.0.0-5.1.0] 0x8000000040000000)	CanExtendSaveData	#ExtendSaveDataFileSystem
[5.0.0+] 0x22	0x8000000000000028 ([1.0.0-5.1.0] 0x0000000080000002)	CanExtendSystemSaveData	#ExtendSaveDataFileSystem
[5.0.0+] 0x23	0x8000000020000000 ([1.0.0-5.1.0] 0x8000000000000000)	CanRegisterUpdatePartition	#RegisterUpdatePartition
[5.0.0+] 0x24	0x8000000040000000 ([1.0.0-5.1.0] 0x8000000000000000)	CanOpenSaveDataTransferManager	#OpenSaveDataTransferManager
[5.0.0+] 0x25	0x8000000200000000 ([1.0.0-5.1.0] 0x8000000080200000)	CanOpenSaveDataTransferManagerVersion2	#OpenSaveDataTransferManagerVersion2
[5.0.0+] 0x26	0x8000000200002000 ([1.0.0-5.1.0] 0x8000000080000110)	CanOpenSaveDataTransferProhibiterForCloudBackUp	#OpenSaveDataTransferProhibiterForCloudBackUp
[5.0.0+] 0x27	0x8000000200002000 ([1.0.0-5.1.0] 0x8000000000100008)	CanListApplicationAccessibleSaveDataOwnerId	ListApplicationAccessibleSaveDataOwnerId
[5.0.0+] 0x28	0x8000000000000000 ([1.0.0-5.1.0] 0x8000000080010000)	CanControlMmcPatrol	#SuspendMmcPatrol, #ResumeMmcPatrol
[5.0.0+] 0x29	0x8000000000000000 ([1.0.0-5.1.0] 0x0000000080000001)	CanOverrideSaveDataTransferTokenSignVerificationKey	#OverrideSaveDataTransferTokenSignVerificationKey
[5.0.0+] 0x2A	0x8000000080200000 ([1.0.0-5.1.0] 0x0000000080000001)	CanOpenSdCardDetectionEventNotifier	#OpenSdCardDetectionEventNotifier
[5.0.0+] 0x2B	0x8000000080000110 ([1.0.0-5.1.0] 0x0000000080000001)	CanOpenGameCardDetectionEventNotifier	#OpenGameCardDetectionEventNotifier
[5.0.0+] 0x2C	0x8000000000100008 ([1.0.0-5.1.0] 0x0000000080000001)	CanOpenSystemDataUpdateEventNotifier	#OpenSystemDataUpdateEventNotifier
[5.0.0+] 0x2D	0x8000000000010000 ([1.0.0-5.1.0] 0x0000000080000001)	CanNotifySystemDataUpdateEvent	#NotifySystemDataUpdateEvent
[5.0.0+] 0x2E	0x8000000100000000 ([1.0.0-5.1.0] 0x8000000040000000)	CanOpenAccessFailureDetectionEventNotifier	#OpenAccessFailureResolver
[5.0.0+] 0x2F	0x8000000100000000 ([1.0.0-5.1.0] 0x8000000080200000)	CanGetAccessFailureDetectionEvent	#GetAccessFailureDetectionEvent
[5.1.0+] 0x30	0x8000000100000000 ([1.0.0-5.1.0] 0x8000000080080000)	CanIsAccessFailureDetected	#IsAccessFailureDetected
[6.0.0+] 0x31	0x8000000100000000	CanResolveAccessFailure	#ResolveAccessFailure
[6.0.0+] 0x32	0x8000000100000000	CanAbandonAccessFailure	#AbandonAccessFailure
[6.0.0+] 0x33	0x8000000040000000	CanQuerySaveDataInternalStorageTotalSize	#QuerySaveDataInternalStorageTotalSize
[6.0.0+] 0x34	0x8000000200000020	CanGetSaveDataCommitId	#GetSaveDataCommitId
[6.0.0+] 0x35	0x8000000000200000	CanSetSdCardAccessibility	#SetSdCardAccessibility
[6.0.0+] 0x36	0x4000000000000000		SimulateGameCardDetectionEvent, SetGameCardSimulationEvent, ClearGameCardSimulationEvent
[6.0.0+] 0x37	0x8000000000080000	CanSetDataStorageRedirectTarget	SetDataStorageRedirectTarget
[6.0.0+] 0x38	0x8000000000000000		#CreateSaveDataFileSystem, CreateSaveDataFileSystemByHashSalt

OpenFileSystem

Takes a type-0x19 input buffer (ContentPath) and a #FileSystemType as parameters. Returns an #IFileSystem.

[2.0.0+] This function was removed.

SetCurrentProcess

Takes a pid-descriptor.

OpenFileSystemWithPatch

Takes an input #FileSystemType and an u64 title-id. Returns an #IFileSystem.

Web-applet loads the #FileSystemType (which must be ContentManual) from u32_table[inparam].

Note: web-applet strings refer to both this cmd and #OpenFileSystemWithId as "MountContent", but official nn_sf_sync symbols use "OpenXX" names.

OpenFileSystemWithId

Takes a type-0x19 input buffer, an #FileSystemType and an u64 title-id. Returns an #IFileSystem.

The #IFileSystem must be ContentMeta if the NCA type is 0 (control).

The input buffer is the output string path from GetApplicationContentPath.

May return errors when attempting to access NCA-paths for an update-title with a gamecard, when the gamecard isn't inserted. May return error 0x7D402 in some cases with update-titles. Non-val2 in32 values with NCA-type1 are unusable, even for normal titles.

The official "MountApplicationPackage" func uses this with in64=0 and #FileSystemType ApplicationPackage.

After the #FileSystemType specific permissions are checked, it then gets the func retval for permissions-type 0x25 and func0.

When #FileSystemType is ContentMeta, it uses in64=0xffffffffffffffff internally, otherwise it checks if in64 is set to 0xffffffffffffffff then throws an error if so. When the in64 used internally is not 0xffffffffffffffff, it's compared with the NCA titleID, then an error is thrown on mismatch.

OpenBisFileSystem

Takes a type-0x19 input buffer string and a u32 Bis partitionID. Official user-process code sets instr[0] = 0 normally. Returns an #IFileSystem.

Only partitionIDs for FAT partitions are usable with this, otherwise error 0x2EE202 is returned. Seems to be about the same as #OpenBisStorage except this mounts the partition filesystem instead of allowing direct access to the partition sectors.

OpenBisStorage

Takes a u32 partition ID, returns 0x2EE202 for partitions which do not exist, 0x320002 for partitions which cannot be opened and a valid #IStorage handle otherwise.

InvalidateBisCache

Seems to invalidate the Bis cache for MBR/GPT after overwriting that data via the OpenBisStorage IStorage. Used by SystemInitializer.

DeleteSaveDataFileSystem

Takes an input u64.

CreateSaveDataFileSystem

Takes a 0x40-byte Save-struct entry, a 0x40-byte SaveCreate-struct entry, and a 0x10-byte input struct.

Only the first 0x5-bytes in the 0x10-byte struct are initialized: all-zero when automatically creating savedata during savecommon mount by official user-processes. In the dedicated save-creation code in official user-processes: +0 u32 = 0x40060, +4 u8 = 1.

Creates regular savedata.

CreateSaveDataFileSystemBySystemSaveDataId

Takes a 0x40-byte Save-struct entry and a 0x40-byte SaveCreate-struct entry.

Creates savedata in the SYSTEM NAND partition.

OpenGameCardStorage

Takes two input u32s (gamecard handle, partition ID), and returns an #IStorage for the partition.

OpenGameCardFileSystem

Takes two input u32s, with the second u32 located at +4 in rawdata after the first u32. Returns an #IFileSystem.

Mounts a gamecard partition.

OpenSaveDataFileSystem

Takes an input u8 #SaveDataSpaceId and a 0x40-byte Save-struct entry. Official user-process code is only known to use value 1 for the u8.

Returns an #IFileSystem.

Permissions aren't checked until the specified save is successfully found.

Only one process (specifically only one #IFileSystem session) can mount a given savedata at any given time (this includes SystemSaveData).

OpenSaveDataFileSystemBySystemSaveDataId

Takes an input u8 #SaveDataSpaceId and a 0x40-byte Save-struct entry. Web-applet only uses value0 for the input u8.

Returns an #IFileSystem.

Mounts savedata in the SYSTEM NAND partition.

ReadSaveDataFileSystemExtraDataBySaveDataSpaceId

Takes an input u8 #SaveDataSpaceId, an input u64 saveID, and a type-0x6 output buffer containing the #SaveDataFileSystemExtraData.

ReadSaveDataFileSystemExtraData

Takes an input u64 saveID and a type-0x6 output buffer containing the #SaveDataFileSystemExtraData.

OpenSaveDataInfoReader

No input, returns an output #ISaveDataInfoReader.

OpenSaveDataInfoReaderBySaveDataSpaceId

Takes an input u8 #SaveDataSpaceId, returns an output #ISaveDataInfoReader.

OpenContentStorageFileSystem

Takes a #ContentStorageId. Invalid values return 0x2EE202.

Returns an #IFileSystem with NCA files. The read data from these files is identical to the data read by NCM_services#ReadContentIdFile.

OpenDataStorageByDataId

Takes a #StorageId and a TitleID.

Returns a domain object ID implementing the #IStorage interface for data archives.

OpenDeviceOperator

This command returns a session to a port implementing the #IDeviceOperator interface.

OpenSdCardDetectionEventNotifier

This command returns a session to a port implementing the #IEventNotifier interface.

OpenGameCardDetectionEventNotifier

This command returns a session to a port implementing the #IEventNotifier interface.

VerifySaveDataFileSystem

Takes an unknown input u64 and a type-0x6 output buffer.

The input u64 high-byte must be non-zero, otherwise an error is returned(0xE02).

GetSaveDataCommitId

Takes an input u8 and u64, returns an output u64.

SetSdCardEncryptionSeed

Takes in the 0x10 byte SD card encryption seed, and loads it into FS-module state.

NS-module reads the 0x10 bytes from SdCard:/Nintendo/Contents/private, and compares them to the first 0x10 bytes of the ns_appman:/private (in system savedata 0x8000000000000043). If they match, NS calls this command using bytes 0x10-0x20 from ns_appman:/private. The rest of this file (0x1F0 bytes total) is (usually/always?) all-zero (however in some cases the byte at offset 0x20 is value 0x1).

SetGlobalAccessLogMode

Takes an input u32.

GetGlobalAccessLogMode

Returns an output u32.

GlobalAccessLogMode is normally 0.

OutputAccessLogToSdCard

Takes a type-0x5 input buffer.

The input buffer is the string to output to the log. User-processes normally include a newline at the end.

User-processes only use this when the value previously loaded from #GetGlobalAccessLogMode has bit1 set.

When bit1 in GlobalAccessLogMode is clear, FS-module will just return 0 for OutputAccessLogToSdCard. However even with that set the log doesn't show up SD, unknown why.

The input buffer is written to the "$FsAccessLog:/FsAccessLog.txt" file, where "$FsAccessLog" is the SD-card mount-name. It's written to the current end of the file(appended).

IStorage

This is "nn::fssrv::sf::IStorage".

This is the interface for a raw device, usually a block device.

Cmd	Name	Arguments
0	Read	Takes a type-0x46 buffer, an offset and length
1	Write	Takes a type-0x45 buffer, an offset and length
2	Flush	None
3	SetSize	Takes a size
4	GetSize	None
5	[4.0.0+] OperateRange

IFileSystem

This is "nn::fssrv::sf::IFileSystem".

There are two main implementations of this interface:

• RomFS: Filesystem implementation statically linked in the binary. Uses an #IStorage interface as underlying raw device.
• IPC proxy: Used for all non-RomFS filesystems. In this case, actual filesystem implementation is in the FS process.

Cmd	Name
0	CreateFile
1	DeleteFile
2	CreateDirectory
3	DeleteDirectory
4	DeleteDirectoryRecursively
5	RenameFile
6	RenameDirectory
7	#GetEntryType
8	#OpenFile
9	#OpenDirectory
10	#Commit
11	#GetFreeSpaceSize
12	#GetTotalSpaceSize
13	[3.0.0+] #CleanDirectoryRecursively
14	[3.0.0+] #GetFileTimeStampRaw
15	[4.0.0+] QueryEntry

GetEntryType

Takes a type-0x9 input buffer for the path and returns #DirectoryEntryType as an output u32.

OpenFile

Takes a type-0x19 input buffer for the path, and an u32 mode. mode controls how the file is opened, based on which bits are set:

• When bit 0 is set, the file is Readable: you can use the Read operation.
• When bit 1 is set, the file is Writable: you can use the Write operation.
• When bit 2 is set, the file is Appendable: unless this bit is set, you will not be able to write beyond the end of a file (such writes will result in an error 0x307202)

OpenDirectory

Takes a type-0x9 input buffer for the path and an u64 filter_flags. filter_flags controls what type of entries are read by the #IDirectory: bitmask 0x1 = directories, bitmask 0x2 = files.

Commit

Like 3DS, this has to be used after writing to savedata for the changes to take affect.

GetFreeSpaceSize

Takes a type-0x9 input buffer for the path and returns an output byte-size u64 for the total free space with this FS.

GetTotalSpaceSize

Takes a type-0x9 input buffer for the path and returns an output byte-size u64 for the total space available with this FS(free+used).

CleanDirectoryRecursively

Takes a type-0x9 input buffer for the path and clears the contents of the directory specified in the path.

GetFileTimeStampRaw

Takes a type-0x19 input buffer for the path and returns a 0x20-byte struct. This contains 3 u64s and an u8.

IDirectory

This is "nn::fssrv::sf::IDirectory".

Cmd	Name
0	#Read
1	#GetEntryCount

Read

Takes a type-0x6 output buffer. Returns an output u64(?) for the total number of read entries, this is 0 when no more entries are available.

The output buffer contains the read array of #DirectoryEntry. This doesn't include entries for "." and "..".

GetEntryCount

Returns an u64 for the total number of readable entries.

DirectoryEntry

Offset	Size	Description
0x0	0x301	Path
0x301	0x3	?
0x304	0x1	#DirectoryEntryType
0x305	0x3	Padding?
0x308	0x8	Filesize, 0 for directories.

DirectoryEntryType

An s8 value indicating a directory entry type. The current values are:

Value	Description
0	Directory
1	File

IFile

This is "nn::fssrv::sf::IFile".

Cmd	Name
0	Read
1	Write
2	Flush
3	SetSize
4	GetSize
5	[4.0.0+] OperateRange

ISaveDataInfoReader

This is "nn::fssrv::sf::ISaveDataInfoReader".

Cmd	Name
0	#ReadSaveDataInfo

ReadSaveDataInfo

Takes a type-0x6 output buffer. Returns an output u64 for total output entries. This buffer contains an array of #SaveDataInfo.

This is used to get #SaveDataInfo for all savedata on the system (or all savedata for the current #SaveDataSpaceId). When used multiple times, it will resume reading where it left off, until no more entries are available (in that case the out u64 is value 0).

IDeviceOperator

This is "nn::fssrv::sf::IDeviceOperator".

Cmd	Name
0	IsSdCardInserted
1	GetSdCardSpeedMode
2	[2.0.0+] GetSdCardCid
3	[2.0.0+] GetSdCardUserAreaSize
4	[2.0.0+] GetSdCardProtectedAreaSize
5	[2.0.0+] GetAndClearSdCardErrorInfo
100	GetMmcCid
101	GetMmcSpeedMode
110	EraseMmc
111	GetMmcPartitionSize
112	[2.0.0+] GetMmcPatrolCount
113	[2.0.0+] GetAndClearMmcErrorInfo
114	[2.0.0+] GetMmcExtendedCsd
115	[4.0.0+] SuspendMmcPatrol
116	[4.0.0+] ResumeMmcPatrol
200	IsGameCardInserted
201	EraseGameCard
202	GetGameCardHandle
203	#GetGameCardUpdatePartitionInfo
204	FinalizeGameCardDriver
205	GetGameCardAttribute
206	GetGameCardDeviceCertificate
207	GetGameCardAsicInfo
208	GetGameCardIdSet
209	WriteToGameCard
210	SetVerifyWriteEnalbleFlag
211	GetGameCardImageHash
212	[2.0.0+] GetGameCardDeviceIdForProdCard
213	[2.0.0+] EraseAndWriteParamDirectly
214	[2.0.0+] ReadParamDirectly
215	[2.0.0+] ForceEraseGameCard
216	[2.0.0+] GetGameCardErrorInfo
217	[2.1.0+] GetGameCardErrorReportInfo
218	[3.0.0+] GetGameCardDeviceId
300	SetSpeedEmulationMode
301	GetSpeedEmulationMode
400	[5.0.0+] SuspendSdmmcControl
401	[5.0.0+] ResumeSdmmcControl
402	[6.0.0+] GetSdmmcConnectionStatus (Takes a total of 4-bytes of input, returns a total of 8-bytes of output)
500	[6.0.0+] SetGameCardSimulationEvent (Takes a total of 0x14-bytes of input, no output)
501	[6.0.0+] ClearGameCardSimulationEvent (Takes a total of 4-bytes of input, no output)

GetGameCardUpdatePartitionInfo

Returns a titleID and the title-version for it.

• Output u32 with ARMS-gamecard: title-version v131162. This is the title-version for 2.1.0, which is the sysupdate included with this gamecard. Launch-day gamecards return title-version v450.
• Output u64 with ARMS-gamecard: titleID 0100000000000816.

NS appears to only use this with Content_Manager_services#GetTitleIdInfo and Content_Manager_services#GetUpdateTitleList with storageid=nandsys, for checking whether a sysupdate is required.

IEventNotifier

This is "nn::fssrv::sf::IEventNotifier".

Cmd	Name
0	GetEventHandle

ISaveDataTransferManager

Cmd	Name
0	#GetChallenge
16	#SetToken
32	#OpenSaveDataExporter
64	#OpenSaveDataImporter

This was added with 4.0.0.

GetChallenge

No input/output, takes a type-0x6 output buffer.

SetToken

No input/output, takes a type-0x5 input buffer.

OpenSaveDataExporter

Takes an input u8 #SaveDataSpaceId and u64, returns an #ISaveDataExporter.

OpenSaveDataImporter

Takes an input u8 #SaveDataSpaceId and a 0x10-byte userID, and a type-0x5 input buffer. Returns an output u64 and an #ISaveDataImporter.

ISaveDataExporter

Cmd	Name
0	#Initialize
1	#GetRestSize
16	#Pull
17	#PullInitialData

This was added with 4.0.0.

Initialize

No input/output, takes a type-0x1A #SaveDataInfo output buffer.

The actual name for this is the SaveDataExporter constructor. This is used automatically after #OpenSaveDataExporter by official sw.

GetRestSize

No input, returns an output u64.

Pull

Takes a type-0x6 output buffer, returns an output u64.

PullInitialData

No input/output, takes a type-0x6 output buffer.

ISaveDataImporter

Cmd	Name
0	#Initialize
1	#GetRestSize
16	#Push
17	#Finalize

This was added with 4.0.0.

Initialize

No input/output, takes a type-0x1A #SaveDataInfo output buffer.

The actual name for this is the SaveDataImporter constructor. This is used automatically after #OpenSaveDataImporter by official sw.

GetRestSize

No input, returns an output u64.

Push

No input/output, takes a type-0x5 input buffer.

Finalize

No input/output.

ISaveDataTransferManagerWithDivision

Cmd	Name
0	#GetChallenge
16	#SetKeySeedPackage
32	#OpenSaveDataFullExporter
33	#OpenSaveDataDiffExporter
34	[6.0.0+] #OpenSaveDataExporterByContext
64	#OpenSaveDataFullImporter
65	#OpenSaveDataDiffImporter
66	[6.0.0+] #OpenSaveDataDuplicateDiffImporter
67	[6.0.0+] #OpenSaveDataImporter
68	[6.0.0+] #OpenSaveDataImporterByContext
69	[6.0.0+] #CancelSuspendingImport

This was added with 5.0.0.

GetChallenge

No input/output, takes a type-0x6 output buffer containing the Challenge.

SetKeySeedPackage

No input/output, takes a type-0x5 input buffer containing the KeySeedPackage.

OpenSaveDataFullExporter

Takes an input u8 #SaveDataSpaceId and u64. Returns an #ISaveDataDivisionExporter.

OpenSaveDataDiffExporter

Takes an input u8 #SaveDataSpaceId, an u64, and a type-0x5 input buffer #InitialDataVersion2. Returns an #ISaveDataDivisionExporter.

OpenSaveDataExporterByContext

No input/output, takes a type-0x5 input buffer, returns an #ISaveDataDivisionExporter.

OpenSaveDataFullImporter

Takes an input u8 #SaveDataSpaceId, a 0x10-byte userID, and a type-0x5 input buffer #InitialDataVersion2. Returns an #ISaveDataDivisionImporter.

OpenSaveDataDiffImporter

Takes an input u8 #SaveDataSpaceId, an u64, and a type-0x5 input buffer #InitialDataVersion2, returns an #ISaveDataDivisionImporter.

OpenSaveDataDuplicateDiffImporter

Takes an input u8 and an u64, and a type-0x5 input buffer, returns an #ISaveDataDivisionImporter.

OpenSaveDataImporter

Takes an input u8, an u8(bool), a 0x10-byte struct, and a type-0x5 input buffer, returns an #ISaveDataDivisionImporter.

OpenSaveDataImporterByContext

No input/output, takes a type-0x5 input buffer, returns an #ISaveDataDivisionImporter.

CancelSuspendingImport

Takes an input u64 and a 0x10-byte struct, no output.

ISaveDataDivisionExporter

Cmd	Name
0	SetDivisionCount (Takes an input u32, no output)
1	[6.0.0+] GetSaveDataInfo (No input/output, takes a type-0x6 output buffer)
16	OpenSaveDataDiffChunkIterator (No input, returns an #ISaveDataChunkIterator)
48	OpenSaveDataChunkExporter (Takes an input u32, returns an #ISaveDataChunkExporter)
64	[6.0.0+] FinalizeFullExport (No input, returns two 0x10-byte output structs)
65	[6.0.0+] FinalizeDiffExport (No input, returns an output 0x10-byte struct)
66	[6.0.0+] CancelExport (No input/output)
67	[6.0.0+] SuspendExport (No input/output, takes a type-0x6 output buffer)
70	[6.0.0+] GetKeySeed (No input, returns an output 0x10-byte struct)
71	[6.0.0+] GetInitialDataMac (No input, returns an output 0x10-byte struct)
72	[6.0.0+] FinalizeExport (No input/output)
80	[6.0.0+] GetImportInitialDataAad (No input, returns an output 0x20-byte struct)
81	[6.0.0+] SetExportInitialDataAad (Takes an input 0x20-byte struct, no output)
96	[6.0.0+] GetReportInfo (No input, returns an output 0x20-byte struct)

This was added with 5.0.0.

ISaveDataDivisionImporter

Cmd	Name
0	[6.0.0+] GetSaveDataInfo (No input/output, takes a type-0x6 output buffer)
16	OpenSaveDataDiffChunkIterator (No input, returns an #ISaveDataChunkIterator)
32	InitializeImport (No input, returns an output u64)
33	FinalizeImport (No input/output)
34	[6.0.0+] CancelImport (No input/output)
35	[6.0.0+] GetImportContext (No input/output, takes a type-0x6 output buffer)
36	[6.0.0+] SuspendImport (No input/output)
48	OpenSaveDataChunkImporter (Takes an input u32, returns an #ISaveDataChunkImporter)
64	[6.0.0+] GetImportInitialDataAad (No input, returns an output 0x20-byte struct)
80	[6.0.0+] GetReportInfo (No input, returns an output 0x20-byte struct)

This was added with 5.0.0.

ISaveDataChunkIterator

Cmd	Name
0	Next (No input/output)
1	IsEnd (No input, returns an output u8)
16	GetId (No input, returns an output u32)

This was added with 5.0.0.

ISaveDataChunkExporter

Cmd	Name
0	Pull (Takes an input u64 and a type-0x6 output buffer, returns an output u64)
16	[6.0.0+] GetRestRawDataSize (No input, returns an output u64)

This was added with 5.0.0.

ISaveDataChunkImporter

Cmd	Name
0	Push (Takes an input u64 and a type-0x5 input buffer, no output)

This was added with 5.0.0.

ISaveDataTransferProhibiter

This was added with 6.0.0.

This doesn't seem to handle any commands (?).

IMultiCommitManager

Cmd	Name
1	? (Takes an input #IFilesystem, no output)
2	? (No input/output)

This was added with 6.0.0.

FileSystemType

Value	Name
0	Invalid
1	Invalid
2	Logo
3	ContentControl
4	ContentManual
5	ContentMeta
6	ContentData
7	ApplicationPackage

StorageId

Value	Name
0	None
1	Host
2	GameCard
3	NandSystem
4	NandUser
5	SdCard

ContentStorageId

Value	Name
0	System
1	User
2	SdCard

SaveDataSpaceId

Value	Name
0	System
1	User
2	SdSystem
100	[3.0.0+] ProperSystem

Determines the storage where the savedata is stored.

SaveDataType

Value	Name
0	SystemSaveData
1	SaveData
2	BcatDeliveryCacheStorage
3	DeviceSaveData
4	[3.0.0+] TemporaryStorage
5	[3.0.0+] CacheStorage

ImageDirectoryId

Value	Name
0	Nand
1	SdCard

CloudBackupWorkStorageId

Value	Name
0	Nand
1	SdCard

ContentPath

These are the 0x300 paths to NCA files for the various filesystems FS can access, beginning with @. They're passed via X descriptors, and returned via various ncm/lr commands.

Path	Notes
@SystemContent
@UserContent
@SdCardContent
@CalibFile
@Safe
@User
@System
@Sdcard
@Host
@GcApp	Gamecard App partition (Partition 2)
@GcS00000001	Gamecard Contents.
@upp	Gamecard update partition (Partition 0)
[4.0.0+] @RegUpdate	Registered update partition

Save Struct

Offset	Size	Description
0x0	0x8	0 for SystemSaveData. SaveData: 0 can be used for accessing the savedata associated with the current FS session titleID, otherwise when set this is the titleID associated with the savedata to access.
0x8	0x10	userID for user-specific savedata(saveuser) when set, otherwise when zero this indicates the common savedata(savecommon). This is loaded from Account_services.
0x18	0x8	u64 saveID. 0 for SaveData.
0x20	0x1	#SaveDataType
0x21	0x1	Save data 'rank' or 'precedence'. 0 if this save data is considered the primary save data. 1 if it's considered the secondary save data.
0x22	0x2	Save data index
0x24	0x4	Padding
0x28	0x8	0 for SystemSaveData/SaveData.
0x30	0x8	0 for SystemSaveData/SaveData.
0x38	0x8	0 for SystemSaveData/SaveData.

Total size is 0x40-bytes.

For DeviceSaveData, this struct is all-zero except for the #SaveDataType field.

SaveCreate Struct

Offset	Size	Description
0x0	0x8	IVFC level4 size?
0x8	0x8	Same as offset 0x0 normally? Hard-coded to 0x80000 for BcatSaveData.
0x10	0x8	0x4000 for SystemSaveData/SaveData/DeviceSaveData/BcatSaveData. IVFC level4 block-size in bytes?
0x18	0x8	Official user-processes only uses 0 here for SystemSaveData/SaveData. For the dedicated save-creation code with SaveData/DeviceSaveData, this value comes from an input param with official user-processes. For BcatSaveData, this is the hard-coded titleID of the bcat-sysmodule.
0x20	0x4	Written using an input param for official user-processes. Hard-coded 0 for BcatSaveData.
0x24	0x1	Official user-processes only uses 0 here for SystemSaveData, 1 for SaveData/DeviceSaveData/BcatSaveData.
0x25	0x1	0 for SystemSaveData/SaveData.
0x26	0x1A	Not initialized for SystemSaveData/SaveData.

Total size is 0x40-bytes.

DeviceSaveData

This is accessed using the same commands for SaveData with the same input u8, the only difference compared to SaveData is the Save-struct.

BcatSaveData

This is accessed using the same commands for SaveData with the same input u8. The Save-struct is the same as DeviceSaveData, except that the titleID field is set to <input titleID>. See above regarding SaveCreate-struct.

The 0x10-byte struct passed to #CreateSaveDataFileSystem has the first 0x5-bytes set to all-zero.

SaveDataInfo

Offset	Size	Description
0x0	0x8	Unknown saveID
0x8	0x1	#SaveDataSpaceId
0x9	0x1	#SaveDataType
0xA	0x6	Padding?
0x10	0x10	userID
0x20	0x8	saveID, 0 for regular SaveData.
0x28	0x8	Application titleID, for regular SaveData.
0x30	0x8	Raw saveimage size
0x38	0x2	Save data index
0x40	0x1	Save data 'rank' or 'precedence'. 0 if this save data is considered the primary save data. 1 if it's considered the secondary save data.
0x41	0x25	Unknown. Usually zeros?

This is a 0x60-byte struct.

SaveDataFileSystemExtraData

This is a 0x200-byte struct. Appears to match Savegames#Extra_data.

InitialDataVersion2

This is a 0x8210-byte struct used by #ISaveDataTransferManagerWithDivision.