DSiWare Exports

The DSiWare exported from a 3DS is located at "sdmc:/Nintendo 3DS/<ID0>/<ID1>/Nintendo DSiWare". Filenames are same format as DSi: "<TitleID-Low>.bin". The below sizes include the 0x20-byte block metadata.

DSiWare exported from 3DS use console-unique keyslots initialized by movable.sed. Each section is encrypted with AES-CBC.

The content sections are ordered the same way as DSi: TMD, SRL from content0, <content1-7 for format v2>, public.sav, and banner.sav when banner.sav exists. When the DSiWare export type is 7-11, the 12th content section is the private.sav, if it exists.(ContentX here is the .app data from TWL-NAND /title)

DSiWare Export Types

Value	Format version	Description
0-6		Same as value 14.
7-11	v2	12 content sections
12	v2	4 content sections
13	v1	4 content sections
14	v2	11 content sections

For NATIVE_FIRM versions where this DSiWare export type field is unused, format version v1 is used with 4 content sections. Otherwise when this field is used, see the above table. System Settings uses type 1 for exporting DSiWare, regardless of the System Settings title-version.

Block Metadata

Offset	Size	Description
0x0	0x10	AES MAC over a SHA-256 hash
0x10	0x10	IV, generated by the RNG.

Each section begins with the payload encrypted data, followed by this block metadata. The SHA-256 hash used for the MAC is calculated over the cleartext payload. This hash used for generating the MAC is also stored in the footer.

Footer

Offset	Size	Description
0x0	X	SHA-256 hashes over the banner, header, and content sections. When a content section doesn't exist, the corresponding hash here is uninitialized.
0x0 + X	0x3C	ECDSA signature using SHA-256 over the previous hashes, signed by the APCert.
0x3C + X	0x180	ECDSA "APXXXXXXXXXXXXXXXX" cert signed by the below CTCert, where X is random lowercase ASCII hex data.
0x1BC + X	0x180	ECDSA CTCert
0x33C + X	0x4	Uninitialized padding.

These hashes are the same hashes used for generating each section's MAC stored in the metadata block. X = 0x40 + totalcontentsections*0x20.

The curve sect233r1 is used for all related ECDSA signing operations

File Structure v1

Offset	Size	Description
0x0	0x4020	Banner section
0x4020	0xC0	Header section
0x40E0	0x340 + 0x20 + X, where X is the total size of the hashes stored in the footer.	Footer section
0x40E0 + footer_size		Content sections

Header

Offset	Size	Description
0x0	0x4	Magic number 0x54444633, "3FDT".
0x4	0x2	Byte-swapped groupID from the TWL TMD.
0x6	0x2	Byte-swapped title version from the TWL TMD.
0x8	0x20	SHA-256 hash calculated over the encrypted movable.sed.
0x28	0x10	Encrypted AES block from encrypting an all-zero 0x10-byte block with AES-CBC, where the IV is all-zero.
0x38	0x8	Byte-swapped titleID from the TWL TMD.
0x40	0x8	?
0x48	0x10	u32 payload sizes for the 4 content sections.
0x58	0x4	?
0x5C	0x3E	Data from the TWL TMD reserved section. Only the first 0x20-bytes from the TWL TMD is written here, the rest is uninitialized.
0x9A	0x6	Padding?

File Structure v2

Offset	Size	Description
0x0	0x4020	Banner section
0x4020	0x110	Header section
0x4130	0x340 + 0x20 + X, where X is the total size of the hashes stored in the footer.	Footer section
0x4130 + footer_size		Content sections

Header

Offset	Size	Description
0x0	0x4	Magic number 0x54444633, "3FDT".
0x4	0x2	Byte-swapped groupID from the TWL TMD.
0x6	0x2	Byte-swapped title version from the TWL TMD.
0x8	0x20	SHA-256 hash calculated over the encrypted movable.sed.
0x28	0x10	Encrypted AES block from encrypting an all-zero 0x10-byte block with AES-CBC, where the IV is all-zero.
0x38	0x8	Byte-swapped titleID from the TWL TMD.
0x40	0x8	?
0x48	0x2C	u32 payload sizes for the 11 content sections.
0x74	0x30	?
0xA4	0x3E	Data from the TWL TMD reserved section. Only the first 0x20-bytes from the TWL TMD is written here, the rest is uninitialized.
0xE2	0x0E	Padding?