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 | Magic "META". |
| 0x4 | 0x8 | Reserved1 |
| 0xC | 1 | Flags |
| 0xD | 1 | UnusedData |
| 0xE | 1 | MainThreadPriority |
| 0xF | 1 | MainThreadCoreNumber |
| 0x10 | 0x8 | Reserved2 |
| 0x18 | 0x4 | Version |
| 0x1C | 0x4 | MainThreadStackSize |
| 0x20 | 0x10 | Title name |
| 0x30 | 0x10 | ProductCode |
| 0x30 | 0x30 | Reserved3 |
| 0x70 | 0x4 | #ACI0 offset |
| 0x74 | 0x4 | #ACI0 size |
| 0x78 | 0x4 | #ACID offset |
| 0x7C | 0x4 | #ACID size |
ACID
| Offset | Size | Description |
|---|---|---|
| 0 | 0x100 | RSA-2048 signature, seems to verify the data starting at 0x100 with the size field from 0x204. |
| 0x100 | 0x100 | RSA-2048 public key, seems to be used for the second NCA signature. |
| 0x200 | 0x4 | Magic "ACID". |
| 0x204 | 0x4 | s32 Size field used with the above signature(?). |
| 0x208 | 0x4 | Zeroes |
| 0x20C | 0x4 | Retail flag. Must be 1 on retail, on devunit 0 is also allowed. |
| 0x210 | 0x8 | Title id |
| 0x218 | 0x8 | Title id again |
| 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 | 4 | #Kernel Access Control offset |
| 0x234 | 4 | #Kernel Access Control size |
| 0x238 | 0x8 | Padding |
ACI0
Looks like an old crappy version of ACID. It has the guessed version field 0 instead of 1.
FS Access Control
| Word | Bit | Description |
|---|---|---|
| 0 | Version? Always 1. | |
| 1 | 0 | MountContent* is accessible when set. |
| 1 | 2 | Enables access to Bis partitionID 27 and 28? |
Web-applets access control:
- "LibAppletWeb" and "LibAppletOff" have same access control: word0 bit0 set, word1 bit0 and bit3 set, and word2 bit30 set.
- Rest of the web-applets: Same as above except word1 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 0x0F 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
|
Kernel flags | 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
|
Syscall mask | Bits 29-31: Syscall mask table index; Bits 5-28: Mask | |
0bxxxxxxxxx0111111
|
Map IO page (RW) | Bits 7-31: Page | |
0bxxxxxxxx01111111
|
Map IO range | Bits 7-30: Alternating start page and number of pages, bit31: Alternating read-only flag then MemoryAttribute 0x2001/0x42002 selector flag | |
0bxxxx011111111111
|
Interrupt pair | Bits 12-21: Irq0, bits 20-31: Irq1, 0x3FF means empty. | |
0xxxx0111111111111
|
|||
0xxx01111111111111
|
|||
0xx011111111111111
|
bit14 | Kernel release version | 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. The raw descriptor is also stored into {state}. This enforces a minimum required version, not a maximum. |
0x0111111111111111
|
bit15 | ||
| All ones | Ignored |
Only certain memory ranges are allowed to be mapped via these descriptors.