NCM services

ncm

Cmd	Name	Notes
0
1
2
3
4	GetContentStorage
5	GetContentMetaDatabase
8
9	InitializeStorageForMediaId
10	UninitializeStorageForMediaId
11	InitializeDatabaseForMediaId
12	UninitializeDatabaseForMediaId

All of the above cmds takes a u8 as input.

IContentStorage

Cmd	Name	Notes
0	#GetRootEntry
1		Takes two 0x10-sized entries, and a u64.
2		Takes a 0x10-sized entry.
3		Takes a 0x10-sized entry, returns a bool/u8.
4		Takes a 0x10-sized entry, a u64, and type-5 array.
5		Takes two 0x10-sized entries.
6	DeleteContent?	Takes a 0x10-sized entry.
7		Takes a 0x10-sized entry, returns a bool/u8.
8		Takes a type-0x1A string and a 0x10-sized entry.
9		Takes a type-0x1A string and a 0x10-sized entry.
10		Void.
11		Takes a type-6 buffer, each entry 0x10 bytes, and returns a u32.
12	#GetNumberOfEntries
13	#GetEntries
14	#GetEntrySize
15		Void.
16		Takes three 0x10-sized entries.
17		Takes a 0x10-sized entry and a u64.
18	#ReadEntryRaw
19		Takes a 0x10-sized entry and returns another 0x10-sized entry.
20	#GetNcaTitleInfo
21		Takes a 0x10-sized entry, a u64, and a type5 buffer.
22	GetFreeSpace
23	GetTotalSpace

GetRootEntry

Returns an entry of 16 completely random-looking bytes. It is not possible to read this entry.

Changes on reboot?

GetNumberOfEntries

Writes the total number of entries which can be read by GetEntries, to cmdreply <SFCO_offset>+0x10.

GetEntries

Takes an output buffer, u32 offset and gets all entries starting at that offset. Returns number of entries read.

Each entry is a #NcaID.

The total read entries is exactly the same as the number of "<hex>.nca" directories in the storage FS(or at least under the "registered" directory?).

GetEntrySize

Takes a #NcaID as input.

Returns the total size readable by ReadEntryRaw. This is the same as the size-field in the NAX0 "<NcaID>.nca/00" file.

ReadEntryRaw

Takes an output buffer, a #NcaID as input, and a u64 file offset.

Returns encrypted looking data from the content in the NAX0. Doesn't match the encrypted raw data in the NAX0 "<NcaID>.nca/00" file. Seems to be at least one crypto layer below the initial NAX0 layer, since the data doesn't change after NAX0 recreation.

Manually modifying the content in the NAX0(starting at offset 0x4000) results in different output data being returned by this cmd. Changing any data within the first 0x10-bytes results in the entire 0x10-byte block changing. Likewise for offset 0x4010 size 0x1, entire 0x10-byte block at 0x4010 changes. Changing the first 0x20-bytes at 0x4000 to zeros has the same combined changed output, as when offset 0x4000 size 0x10 and offset 0x4010 size 0x10 were changed to zeros separately. Output BlockA and BlockB are completely different, where the raw NAX0 data for those blocks are all-zero.

Overwriting the entire raw NAX0 content with zeros results in output data which doesn't seem to have any duplicate blocks/data. When changing the previously mentioned raw content for the first 8 blocks to last-block-byte = 1<<i, where i is 0-7, none of the changed output blocks match any output blocks from the previously mentioned output(all-zero raw content).

This implies that that an AES mode is being used which isn't CTR, where changing data in one block doesn't affect other blocks.

See GetEntrySize for the total size readable with this.

GetNcaTitleInfo

Takes a #NcaID and returns the following 0x10-sized entry.

With some NcaIDs this may return 0 with an all-zero output entry. This seems to be the case for most/all (?) NandSystem NcaIds?

Offset	Size	Description
0x0	0x8	Big-endian titleID
0x8	0x8	Unknown. Usually zero?

IContentMetaDatabase

Cmd	Name	Notes
0	InsertContentEntry?	Takes a 0x10-sized entry, a type-5 buffer and a u64.
1		Takes a 0x10-sized entry, a type-6 buffer and a u64. Returns a u64.
2		Takes a 0x10-sized entry.
3		Takes a 0x10-sized entry and a bool/u8. Returns an 0x10-sized entry.
4		Takes a type-6 buffer, each entry being 24 bytes, 0x10-sized entry and a u32. Returns a u32.
5	Iterate	Takes a type-6 buffer, each entry being 16 bytes, a 0x10-sized entry, and a u32. Returns a u32.
6	#GetTitleIdInfo
7	#GetTitleList	Takes a type-6 buffer, each entry being 24 bytes, and a u8/bool. Returns two u32's.
8		Takes a 0x10-sized entry. Returns a bool/u8.
9		Takes a type-5 buffer, each entry being 16 bytes. Returns a bool/u8.
10		Takes a 0x10-sized entry. Returns a u64.
11		Takes a 0x10-sized entry. Returns a u32.
12		Takes a 0x10-sized entry. Returns a u64.
13		Void.
14		Takes a type-6 byte buffer, and a type-5 buffer with each entry being 16 bytes.
15	EndIteration	Void.
16		Takes two 0x10-sized entries. Returns a bool/u8.
17		Takes a type-6 buffer, each entry being 16 bytes, a 0x10-sized entry and a u32. Returns a u32.
18		Takes a 0x10-sized entry. Returns a bool/u8.
19		Takes a 0x10-sized entry. Returns a u32.

GetTitleIdInfo

Takes a u64 title-id as input, returns same title-id together with info struct.

struct title_info {
  u32  version;
  u8   type;
  u8   pad[3];
};

GetTitleList

Each 24-byte entries is as follows:

 u64    title_id_update;
 struct title_info info;
 u64    title_id;

NcaID

This is a 0x10-byte entry. This is originally from the hex portion of "<hex>.nca" directory-names from this storage FS(like SD).

Enums

Title Types

Value	Description
0x01	System executable titles? (Titles with TID 01000000000000XX or 01000000000010XX)
0x02	System Data Archives
0x03	Unknown. Only used for title 0100000000000816?
0x04	Firmware package A
0x05	Firmware package B
0x80	Regular application
0x81	Update title