Config Savegame

This page describes the format of the Cfg NAND savegame. These blocks can be accessed with the Cfg service commands.

Structure of save-file "/config"

Offset	Size	Description
0x0	0x2	Total entries
0x2	0x2	Data entries offset
0x4	0x4558	Block entries
0x455C		Data for the entries

The filesize for this /config file is 0x8000-bytes.

Configuration block entry

Offset	Size	Description
0x0	0x4	BlkID
0x4	0x4	Offset to the data for this block when size is >4, otherwise this word is the data for this block
0x8	0x2	Size
0xA	0x2	Flags

Configuration blocks

BlkID	Size	Flags	Description
0x00000000	0x2	0xC	Config savegame version?
0x00010000	0x1	0xC	?
0x00020000	0x134	0xC	?
0x00030000	0x1	0xC	?
0x00030001	0x8	0xE	User time offset (read by CECD)
0x00030002	0x8	0xC	?
0x00040000	0x10	0xC	? (read by HID)
0x00040001	0x1C	0xC	Analog Stick Calibration Param?(read by HID)
0x00040002	0x12	0xC	? (read by HID)
0x00040003	0xC	0xC	? (read by HID)
0x00040004	0x1C	0xC	?
0x00050000	0x2	0xC	Upper/Lower screen flicker byte
0x00050001	0x2	0xC	Backlight controls (u8 ABL_powersave_enable, u8 brightness_level) (read by GSP)
0x00050002	0x38	0xC	? (read by GSP)
0x00050003	0x20	0xC	? (read by GSP)
0x00050004	0x20	0xC	?
0x00050005	0x20	0xE	Stereo display settings
0x00050006	0x2	0xC	?
0x00050007	0x4	0xC	?
0x00050008	0x10C	0xC	?
0x00050009	0x8	0xC	new3DS only(?) backlight control (5th byte: backlight dimming enable)
0x00060000	0x96	0xC	?
0x00070000	0x214	0xE	?
0x00070001	0x1	0xE	Sound output mode (mono/stereo/surround)?
0x00070002	0x8	0xE	?
0x00080000	0xC00	0xC	WiFi configuration slot 0
0x00080001	0xC00	0xC	WiFi configuration slot 1
0x00080002	0xC00	0xC	WiFi configuration slot 2
0x00090000	0x8	0xE	This contains a u64 ID, used by processes using NWMUDS:InitializeWithVersion. The first word is the same as LocalFriendCodeSeed, while the latter is a separate word.
0x00090001	0x8	0xE	Same content as 0x0009000? This console-unique u64 is used by GenHashConsoleUnique. It is generated by ((0x3FFFFFFFF) & LocalFriendCodeSeed) | (random16 << 48)), where random16 is generated by GenerateRandomBytes
0x00090002	0x4	0xE	The first two bytes are the same random16 used in 0x00090001. The second two bytes are zeros.
0x000A0000	0x1C	0xE	Username in UTF16
0x000A0001	0x2	0xE	Birthday (u8 month, u8 day)
0x000A0002	0x1	0xE	Language
0x000B0000	0x4	0xE	CountryInfo
0x000B0001	0x800	0xE	Country name in UTF-16, every 0x80-bytes is an entry for each language, in the order of the Language table below (not all entries are set)
0x000B0002	0x800	0xE	State name in UTF-16, every 0x80-bytes is an entry for each language
0x000B0003	0x4	0xE	Coordinates. A pair of s16 represents latitude and longitude, respectively. One need to multiply both value by 180/32768 to get coordinates in degrees
0x000C0000	0xC0	0xE	Restricted photo exchange data, and other info (includes a mirror of Parental Restrictions PIN/Secret Answer)
0x000C0001	0x14	0xE	Same as above?
0x000C0002	0x200	0xE	? Contains the email address set during Parental Restriction setup.
0x000D0000	0x4	0xE	u16 at offset 0x0: EULA Version which was agreed to.
0x000E0000	0x1	0xE	?
0x000F0000	0x10	0xC	Debug configuration, read by NS on dev-units: on startup, NS does svcKernelSetState(6, 1, (u64)debug_flags & 1); svcKernelSetState(6, 2, (u64)debug_flags & 2); (see here) where debug_flags is the u32 located at offset 0xC in this struct. Then it compares the u32 from +8 in this config-block with the APPMEMTYPE. When those don't match NS starts a FIRM-launch (with the same FIRM titleID as the currently running one) to boot into a FIRM with the APPMEMTYPE value from this config-block. The byte at offset 0x0 is related to the memtype as well.
0x000F0001	0x8	0xC	?
0x000F0003	0x1	0xC	?
0x000F0004	0x4	0xC	The first u8 is the System-Model value, the last 3-bytes are unknown
0x000F0005	0x4	0xC	The first u8 indicates whether network updates are enabled (however, NIM only checks this flag with developer ENVINFO).
0x000F0006	0x28	0xC	?
0x00100000	0x2	0xC	?
0x00100001	0x94	0xC	Stores Parental Restrictions PIN/Secret Answer and other info
0x00100002	0x1	0xC	?
0x00100003	0x10	0xC	?
0x00110000	0x4	0xC	The low u16 indicates whether the system setup is required, such as when the system is booted for the first time or after doing a System Format: 0 = setup required, non-zero = no setup required
0x00110001	0x8	0xC	TitleID of the menu to launch, used by NS on dev units (this block can be edited on dev units with Config)
0x00120000	0x8	0xC	? (read by HID)
0x00130000	0x4	0xE	If response is 0x100 then debug mode is enabled.
0x00150000	0x4	0xC	?
0x00150001	0x8	0xC	?
0x00150002	0x4	0xE	?
0x00160000	0x4	0xE	Unknown, first byte is used by config service-cmd 0x00070040. (Unknown whether the last 3-bytes are used)
0x00170000	0x4	0xE	?
0x00180000	0x4	0xC	?
0x00180001	0x18	0xC	?
0x00190000	0x1	0xC	Unknown. NFC-module checks for value1/non-value1.

The developer unit TID block only exists on developer units.

Stereo Display Settings

All values are hard-coded in cfg module.

Offset	Size	Value	Description
0x0	4	62.0f	assumed pupillary distance in mm?
0x4	4	289.0f	assumed distance in mm between player's eyes and upper screen?
0x8	4	76.80f	width in mm of (old) 3DS upper screen (doesn't vary for different models?)
0xC	4	46.08f	height in mm of (old) 3DS upper screen (doesn't vary for different models?)
0x10	4	10.0f
0x14	4	5.0f
0x18	4	55.58f
0x1C	4	21.57f

Languages

ID	Description
0	JP
1	EN
2	FR
3	DE
4	IT
5	ES
6	ZH
7	KO
8	NL
9	PT
10	RU
11	TW

CountryInfo

Byte	Description
0	?
1	?
2	State/Province code.
3	Country code, same as DSi/Wii country codes. Value 0xFF is invalid.

0x000A0000 Block

Byte	Description
0x0-0x13	UTF-16 username, with no NULL-terminator.
0x14-17	Usually zero?
0x18-0x1B	u32 NGWord version the username was last checked with. If this value is less than the u32 stored in the NGWord CFA "romfs:/version.dat", the system then checks the username string with the bad-word list CFA again, then updates this field with the value from the CFA

WiFi Slot Structure

Network structure

This is used twice in the actual WiFi slot structure.

Offset	Size	Description
0x0	0x1	Whether the network was set or not?
0x1	0x1	Whether to use this network strucutre to connect?
0x2	0x1	Whether this structure is the first (0) or the second (1) in the larger WiFi slot structure?
0x3	0x1	Padding ?
0x4	0x20	SSID of the network, without a trailing nullbyte.
0x24	0x1	Length of the SSID.
0x25	0x1	AP crypto key type
0x26	0x2	Padding ?
0x28	0x40	Plaintext of the passphrase of the network, without a trailing nullbyte.
0x68	0x20	PBKDF2 of the passphrase and SSID (http://jorisvr.nl/wpapsk.html).

Actual structure

Offset	Size	Description
0x0	0x2	?
0x2	0x2	CRC-16 checksum of the next 0x410 bytes.
0x4	0x88	First network structure. Only set if the network was set "normally", or was the last to be set using WPS during the session.
0x8C	0x20	Padding.
0xAC	0x88	Second network structure. Only set if the network was set using WPS, otherwise 0-filled.
0x134	0x20C	Padding.
0x340	0x1	Whether to automatically get the IP address (use DHCP) or not, defaults to 1.
0x341	0x1	Whether to automatically get the DNS or not, defaults to 1.
0x342	0x2	Padding ?
0x344	0x4	IP address, to use if 0x340 is false.
0x348	0x4	IP address of the gateway, to use if 0x340 is false.
0x34C	0x4	Subnetwork mask, to use if 0x340 is false.
0x350	0x4	IP address of the primary DNS , to use if 0x341 is false.
0x354	0x4	IP address of the secondary DNS, to use if 0x341 is false.
0x358	0x4	Always 0x01050000 ? Only set if the network was the last to be set during the session.
0x35C	0x4	IP address to use. Only set if the network was the last to be set during the session.
0x360	0x6	MAC address of the AP. Only set if the network was the last to be set during the session.
0x366	0x1	Channel. Only set if the network was the last to be set during the session.
0x367	0x1	Padding ? Only set if the network was the last to be set during the session.
0x368	0x1	Whether to use a proxy or not, defaults to 0.
0x369	0x1	Whether to use a basic authentication for the proxy, defaults to 0.
0x36A	0x2	Port to use for the proxy, defaults to 1.
0x36C	0x30	URL/address of the proxy, including a trailing nullbyte.
0x39C	0x34	Padding.
0x3D0	0x20	Username to use for basic authentication, including a trailing nullbyte.
0x3F0	0x20	Password to use for basic authentication, including a trailing nullbyte.
0x410	0x2	Padding ?
0x412	0x2	MTU value, defaults to 1400 and ranges between 576 and 1500, inclusive.
0x414	0x7EC	Padding.

LCD display config

There seems to be some sort of LCD display configuration stored in this cfg. When using the cfg-save from an Old3DS on a New3DS without formatting the cfg first, the bottom-screen display is somewhat off(which is fixed by formatting the cfg-save).

Parental control Block 0x00100001

Byte	Size in bytes	Description
0x0	0xD	Unknown.
0xD	0x4	PIN
0x11	0x20	Secret answer in UTF-16