NPDM

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This is the Switch equivalent of 3DS exheader. This is the file with extension ".npdm" in {Switch ExeFS}. The size of this file varies.

Offset Size Description
0x0 0x80 META
0x80 <Varies> ACID
<See META> <See META> ACI0

META

Offset Size Description
0x0 0x4 Magicnum "META"
0x4 0x4 [9.0.0+] AcidSignatureKeyGeneration (0 or 1)
0x8 0x4 Reserved
0xC 0x1 Flags
0xD 0x1 Reserved
0xE 0x1 MainThreadPriority
0xF 0x1 MainThreadCoreNumber
0x10 0x4 Reserved
0x14 0x4 [3.0.0+] SystemResourceSize
0x18 0x4 Version
0x1C 0x4 MainThreadStackSize
0x20 0x10 Name (usually/always "Application")
0x30 0x10 ProductCode (usually/always all zeroes)
0x40 0x30 Reserved
0x70 0x4 AciOffset
0x74 0x4 AciSize
0x78 0x4 AcidOffset
0x7C 0x4 AcidSize

Flags

Bits Description
0 Is64BitInstruction
1-3 ProcessAddressSpace (0x00 = AddressSpace32Bit, 0x01 = AddressSpace64BitOld, 0x02 = AddressSpace32BitNoReserved, 0x03 = AddressSpace64Bit)
4 OptimizeMemoryAllocation

MainThreadPriority

Ranges from 0 to 0x3F.

SystemResourceSize

This is the size of PersonalMmHeap. Maximum size as of 5.0.0 is 0x1FE00000.

Version

0 for all titles.

[8.1.0+] Now set to 1 for certain titles.

[9.0.0+] Now set to a proper version field for all titles.

MainThreadStackSize

Must be aligned to 0x1000.

In non-nspwn scenarios, values of 0 can also rarely break in Horizon. This might be something auto-adapting or a security feature of some sort?

ACID

Offset Size Description
0x0 0x100 RSA-2048 signature over the data starting at 0x100 with the size field from 0x204
0x100 0x100 RSA-2048 public key for the second NCA signature
0x200 0x4 Magicnum "ACID"
0x204 0x4 Size
0x208 0x4 Reserved
0x20C 0x4 Flags
0x210 0x8 ProgramIdMin
0x218 0x8 ProgramIdMax
0x220 0x4 FsAccessControlOffset
0x224 0x4 FsAccessControlSize
0x228 0x4 SrvAccessControlOffset
0x22C 0x4 SrvAccessControlSize
0x230 0x4 KernelCapabilityOffset
0x234 0x4 KernelCapabilitySize
0x238 0x8 Reserved

Flags

Bits Description
0 ProductionFlag
1 UnqualifiedApproval
2-3 [5.0.0+ ] MemoryRegion (0 = Application, 1 = Applet, 2 = SecureSystem, 3 = NonSecureSystem)

MemoryRegion is set to Application for "starter" and NonSecureSystem for "nvservices".

ACI0

Offset Size Description
0x0 0x4 Magicnum "ACI0"
0x4 0xC Reserved
0x10 0x8 ProgramId
0x18 0x8 Reserved
0x20 0x4 FsAccessControlOffset
0x24 0x4 FsAccessControlSize
0x28 0x4 SrvAccessControlOffset
0x2C 0x4 SrvAccessControlSize
0x30 0x4 KernelCapabilityOffset
0x34 0x4 KernelCapabilitySize
0x38 0x8 Reserved

FsAccessControl

For ACID this is a simple descriptor as follows:

Offset Size Description
0x0 0x1 Version (always 1, must be non-zero)
0x1 0x1 ContentOwnerIdCount
0x2 0x1 SaveDataOwnerIdCount
0x3 0x1 Padding
0x4 0x8 FsAccessFlag
0xC 0x8 ContentOwnerIdMin
0x14 0x8 ContentOwnerIdMax
0x1C 0x8 SaveDataOwnerIdMin
0x24 0x8 SaveDataOwnerIdMax
0x2C 0x8 * ContentOwnerIdCount ContentOwnerIds
Variable 0x8 * SaveDataOwnerIdCount SaveDataOwnerIds

For ACI0 this embeds data as follows:

Offset Size Description
0x0 0x1 Version (always 1, must be non-zero)
0x1 0x3 Padding
0x4 0x8 FsAccessFlag
0xC 0x4 ContentOwnerInfoOffset
0x10 0x4 ContentOwnerInfoSize
0x14 0x4 SaveDataOwnerInfoOffset
0x18 0x4 SaveDataOwnerInfoSize
0x1C 0x4 (Optional) ContentOwnerIdCount
0x1C 0x8 * ContentOwnerIdCount ContentOwnerIds
Variable 0x4 SaveDataOwnerIdCount
Variable 0x1 * SaveDataOwnerIdCount Accessibilities (1=Read, 2=Write, 3=ReadWrite)
Variable (padded to nearest 4 bytes) 0x8 * SaveDataOwnerIdCount SaveDataOwnerIds

FsAccessFlag

Bits Name Description
0 ApplicationInfo MountContent* is accessible when set.
1 BootModeControl
2 Calibration
3 SystemSaveData
4 GameCard
5 SaveDataBackUp
6 SaveDataManagement
7 BisAllRaw
8 GameCardRaw
9 GameCardPrivate
10 SetTime
11 ContentManager
12 ImageManager
13 CreateSaveData
14 SystemSaveDataManagement
15 BisFileSystem
16 SystemUpdate
17 SaveDataMeta
18 DeviceSaveData
19 SettingsControl
20 SystemData
21 SdCard
22 Host
23 FillBis
24 CorruptSaveData
25 SaveDataForDebug
26 FormatSdCard
27 GetRightsId
28 RegisterExternalKey
29 RegisterUpdatePartition
30 SaveDataTransfer
31 DeviceDetection
32 AccessFailureResolution
33 SaveDataTransferVersion2
34 RegisterProgramIndexMapInfo
35 CreateOwnSaveData
36 MoveCacheStorage
37-61 Reserved
62 Debug See here.
63 FullPermission Enables access to everything: all permission types which check a bitmask have this bit set.

Controls the filesystem permissions.

Web-applets permissions:

  • "LibAppletWeb" and "LibAppletOff" have same access control: bit0 and bit3 set, and bit62 set.
  • Rest of the web-applets: Same as above except bit0 isn't set.

Service Access Control

Bits Description
0-2 Size (length of the service-name without null-terminator minus 1)
7 IsServer (service is allowed to be registered)
Variable Name

This is a list of service-name strings which the title has access to.

The service name string starts after the first byte and supports the wildcard * character.

KernelCapability

Pattern of lower bits Lowest clear bitmask/bit Description
0bxxxxxxxxxxxx0111 Bit3 #ThreadInfo
0bxxxxxxxxxxx01111 Bit4 #EnableSystemCalls
0bxxxxxxxxx0111111 Bit6 #MemoryMap
0bxxxxxxxx01111111 Bit7 #IoMemoryMap
0bxxxxx01111111111 Bit10 [8.0.0+] #MemoryRegionMap
0bxxxx011111111111 Bit11 #EnableInterrupts
0bxx01111111111111 Bit13 #MiscParams
0bx011111111111111 Bit14 #KernelVersion
0b0111111111111111 Bit15 #HandleTableSize
0b1111111111111111 Bit16 #MiscFlags
All ones Invalid

These descriptors are identified by pattern 01..11 in low bits.

ThreadInfo

Bits Description
4-9 LowestPriority
10-15 HighestPriority
16-23 MinCoreNumber
24-31 MaxCoreNumber

EnableSystemCalls

Bits Description
5-28 SystemCallId
29-31 Index

MemoryMap

MemoryMap entries are stored in pairs. The first pair will contain BeginAddress and PermissionType, while the second pair will contain Size and MappingType.

Bits Description
7-30 BeginAddress
31 PermissionType (0=RW, 1=RO)
Bits Description
7-26 Size
27-30 Reserved
31 MappingType (0=Io, 1=Static)

Restrictions

The physaddr range 0x80060000-0x2000000000 is not allowed to be mapped as IO. The physaddr range 0x80000000-0x2000000000 is not allowed to be mapped as Normal.

[2.0.0-4.1.0] The range for IO was changed into 0x80060000-0x81D3FFFF.

[2.0.0-4.1.0] A blacklist was added for IO and Normal mappings:

  • 0x50040000-0x50060000 (ARM, Interrupt Controller)
  • 0x6000F000 (Exception Vectors)
  • 0x6001DC00-0x6001E000 (IPATCH)
  • 0x7000E000 (RTC/PMC)
  • 0x70019000 (MC)
  • 0x7001C000 (MC0)
  • 0x7001D000 (MC1)

[5.0.0+] For IO, this blacklist was abandoned and instead two range checks were added. For Normal mappings it is still applied

IoMemoryMap

Bits Description
8-31 BeginAddress

MemoryRegionMap

Bits Description
11-16 RegionType0 (0 = NoMapping, 1 = KernelTraceBuffer, 2 = OnMemoryBootImage, 3 = DTB)
17 RegionIsReadOnly0
18-23 RegionType1 (0 = NoMapping, 1 = KernelTraceBuffer, 2 = OnMemoryBootImage, 3 = DTB)
24 RegionIsReadOnly1
25-30 RegionType2 (0 = NoMapping, 1 = KernelTraceBuffer, 2 = OnMemoryBootImage, 3 = DTB)
31 RegionIsReadOnly2

MemoryRegionMap is supported by the kernel but not by Loader. Thus, only initial processes may possess this capability.

EnableInterrupts

Bits Description
12-21 InterruptNumber0
22-31 InterruptNumber1

0x3FF means empty.

MiscParams

Bits Description
14-16 ProgramType (0 = System, 1 = Application, 2 = Applet)

ProgramType is parsed by Process Manager services. Defaults to 0 if descriptor doesn't exist. Can only run 1 application at a time.

KernelVersion

Bits Description
15-18 MinorVersion
19-31 MajorVersion

This is compared with 0x80000, when less than an error is returned. This is equivalent to comparing the bits starting at bit15 with 0x10. This enforces a minimum required version, not a maximum.

Versions

Firmware Kernel Version Minimum Allowed
1.0.0 5.0.0 3.0.0
2.0.0 6.1.0 3.0.0
3.0.0 7.4.0 3.0.0
3.0.2 7.4.0 3.0.0
5.0.0 9.3.0 3.0.0

HandleTableSize

Bits Description
16-25 HandleTableSize

MiscFlags

Bits Description
17 EnableDebug
18 ForceDebug
Retrieved from "https://switchbrew.org/w/index.php?title=NPDM&oldid=9411"