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

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	Data size
0x208	0x4	Reserved
0x20C	0x4	Flags (bit0 = ProductionFlag, bit1 = UnqualifiedApproval, [5.0.0+] bit2-3: PoolPartition? For applets set to 0b01, for sysmodules set to 0b10. Exceptions: "starter" is set to 0, "nvservices" is set to 3)
0x210	0x8	TitleIdRange_Min
0x218	0x8	TitleIdRange_Max
0x220	0x4	#FS Access Control offset
0x224	0x4	#FS Access Control size
0x228	0x4	#Service Access Control offset
0x22C	0x4	#Service Access Control size
0x230	0x4	#Kernel Access Control offset
0x234	0x4	#Kernel Access Control size
0x238	0x8	Reserved

ACI0

Offset	Size	Description
0x0	0x4	Magicnum "ACI0"
0x4	0xC	Reserved
0x10	0x8	Title ID
0x18	0x8	Reserved
0x20	0x4	#FS Access Header offset
0x24	0x4	#FS Access Header size
0x28	0x4	#Service Access Control offset
0x2C	0x4	#Service Access Control size
0x30	0x4	#Kernel Access Control offset
0x34	0x4	#Kernel Access Control size
0x38	0x8	Reserved

FS Access Header

Offset	Size	Description
0x0	0x1	Version (always 1, must be non-zero)
0x1	0x3	Padding
0x4	0x8	Permissions bitmask
0xC	0x4	Data Size (always 0x1C)
0x10	0x4	Size of Content Owner ID section.
0x14	0x4	Data size (0x1C) plus Content Owner size
0x18	0x4	Size of Save Data owners section (for applications that wish to share save data?)
0x1C	0x4	(OPTIONAL) Amount of content owner id's
0x1C	0x8 * Content Owner ID's	Content owner ID's as uint64's.
VARIABLE	0x4	Amount of save owner id's
VARIABLE	0x1 * Save data owner accessibilities (?)	Sets flags for what save data owners can do with other applications save data (?)
VARIABLE (Pad to nearest 4 bytes)	0x8 * Amount of save owner ID's	Save data owner ID's

FS Access Control

Offset	Size	Description
0x0	0x1	Version (always 1, must be non-zero)
0x1	0x3	Padding
0x4	0x8	Permissions bitmask
0xC	0x20	Reserved

Permissions bitmask:

Bit	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
34-61	Reserved
62	Debug	See here.
63	FullPermission	Enables access to everything: all permission types which check a bitmask have this bit set.

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

This is a list of service-name strings which the title has access to, with the following structure:

 +0: control_byte
 +1: {service-name without nul-terminator}

Bitmask 0x07 in control_byte is the {length of the service-name without nul-terminator} - 1.

Bitmask 0x80 in control_byte means service is allowed to be registered.

The service string can contain a wildcard * character.

Kernel Access Control

On Switch, descriptors are identified by pattern 01..11 in low bits.

Pattern of lower bits	Lowest clear bitmask/bit	Type	Fields
`0bxxxxxxxxxxxx0111`	Bit3	KernelFlags	Bit31-24: Highest allowed cpu id, bit23-16: Lowest allowed cpu id, bit15-10: Highest allowed thread prio, bit9-4: Lowest allowed thread prio
`0bxxxxxxxxxxx01111`	Bit4	SyscallMask	Bits 29-31: Syscall mask table index; Bits 5-28: Mask
`0bxxxxxxxxx0111111`	Bit6	MapIoOrNormalRange	Bits 7-30: Alternating start page and number of pages, bit31: Alternating read-only flag then MemoryAttribute 0x2001/0x42002 selector flag
`0bxxxxxxxx01111111`	Bit7	MapNormalPage (RW)	Bits 8-31: Page
`0bxxxx011111111111`	Bit11	InterruptPair	Bits 12-21: Irq0, bits 22-31: Irq1, 0x3FF means empty.
`0bxx01111111111111`	Bit13	ApplicationType	Bit16-14: ApplicationType (0=sysmodule, 1=application, 2=applet), bit16 ignored. Parsed by Process Manager services. Defaults to 0 if descriptor doesn't exist. Can only run 1 application at a time.
`0bx011111111111111`	Bit14	KernelReleaseVersion	Bits 15-X: Version. The raw descriptor 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.
`0b0111111111111111`	Bit15	HandleTableSize	Bit25-16: Number of handles the table shall fit.
`0b1111111111111111`	Bit16	DebugFlags	Bit17: can be debugged, bit18: can debug others
All ones		Ignored

Mapping 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

Kernel 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

Bit31-19: Major version
Bit18-15: Minor version
Bit14-0: Zeroes

NPDM

Contents

META