.bin is a basic format used to store the data in Fire Emblem Awakening and Fire Emblem Fates.

.bin file format is pointer-based. All data are stored in little endian format.

Offset	Size	Description
0x0	20	Header
0x20	D	Data region
0x20 + D	P1 * 4	Pointer region 1
0x20 + D + P1 * 4	P2 * 8	Pointer region 2
0x20 + D + P1 * 4 + P2 * 8	remainder	End region

D, P1, P2 are determined in the file's header.

Offset	Size	Description
0x0	4	File size
0x4	4	Data region size (D)
0x8	4	Pointer count 1 (P1)
0xC	4	Pointer count 2 (P2)
0x10	16	Padding

Pointer region 1 is a list of all pointers in the data region. In all official files, this list was sorted in the following procedure:

• Pointers that pointed to somewhere in the data region (e.g. support table in GameData.bin)
  • Sort those pointers in ascending order.
  • Add them into the list.
• Label pointers:
  • Group all label pointers that pointed to the same label into a group.
  • Sort all pointers in each group, in ascending order.
  • Sort those groups by the lowest pointer in the group, in ascending order.
  • Add all pointer groups into the list.

The sorting process is supposed to make the file easier to read, although it isn't necessary. An .bin file with unsorted pointer region 1 will work without any problem.

There are P2 number of the following structure:

Offset	Size	Description
0x0	4	Data block offset (relative to the data region offset, i.e. 0x20)
0x4	4	Label offset (relative to the end region offset)

In the official files, all structures are sorted by data block offset, in ascending order. It is unknown whether or not an unsorted pointer region 2 works.

The end region of all official .bin files only contains labels. Each label is a null-terminated string in Shift-JIS encoding, and is referenced somewhere in data region. Because this format is pointer-based, the end region may contains data that are not labels, pointed from certain pointer in data region.

In the official files, all labels are sorted as follows:

• Sort all labels that are referenced in pointer region 2, in the order of that region.
• Sort the rest of the labels, following the order of the pointers in data region.

Similar to the pointer region 1, label sorting is not necessary.

GameData/GameData.bin (can be downloaded from this repository)

Offset	Size	Description
0x0	4	File size (0x32FF7)
0x4	4	Data region size (0x1EE88)
0x8	4	Pointer count 1 (0x1264)
0xC	4	Pointer count 2 (0x519)
0x10	16	Padding
0x20	0x1EE88	Data region
0x1EEA8	0x1264 * 4	Pointer region 1
0x23838	0x519 * 8	Pointer region 2
0x26100	0xCEF7	Label region

Offset	Value	+0x20	Data region	+0x20	Description
0x1EEA8	0x0	0x20	0x64	0x84	Chapter data pointer
0x1EEAC	0x8	0x28	0xDC0	0xDE0	Character data pointer
...	...	...	...	...	...
0x1F83C	0x64	0x84	0x260E0	0x26100	CID_NONE (default chapter label)

Explanation: The value at offset 0x1EEA8 in the GameData.bin file is 0x0. Add that value to 0x20, the result is 0x20. The value at offset 0x20 in the GameData.bin file is 0x64. Again, add 0x20 to 0x64, the result is 0x84. The block that is at offset 0x84 is chapter data.

Offset	Data block offset (relative)	Data block offset (relative) + 0x20	Description	Label offset (relative)	Label offset (relative) + First label offset	Description
0x23838	0x64	0x84	"None" chapter block offset	0x0	0x26100	CID_NONE ("None" chapter label)
...	...	...	...	...	...	...
0x25240	0x14FB0	0x14FD0	Bronze Sword block offset	0x2D5E	IID_青銅の剣 (Bronze Sword label)

Some Nightmare modules in this repository supports in-place editing in the data region for certain files.

Because .bin file format is pointer-based, it's possible to redirect the pointer in certain part of the data region to the end of file, add some data there, then modify the file size in the header. It's the easiest way to expand the data, and is known to work. The first successful modification was done by TildeHat on gbatemp forum.^[1] The GameData.bin file in the same-sex marriage project was modified using the same technique. Support table was redirected to the end of file, then custom support was added.

However, if you want to add new data that contains pointer, you need to add more pointer to the pointer regions. For GameData.bin editing, it's recommended to use gamedata_module.py in this repository to add new data. It automatically resize the file and fixed all pointers.

• GameData/GameData.bin: Store the most important data in the game, like characters, items, etc.
• GameData/AcceShop.bin: Accessory data in Accessory Shop.
• All .bin files in GameData/Person folder: Store the unit data in specific map.
• All .bin files in GameData/Dispos folder: Unit distribution in specific map.
• All .bin files in GameData/Terrain folder: Terrain data in specific map.
• All .bin files in m folder: Contains the game's text. Can be dumped to text files using FEAT.
• castle/castle_person.bin: Data of all possible people in My Castle
• castle/castle_join.bin: Handles all character that joins the user's party via My Castle.
• castle/castle_building.bin: All building data in My Castle can be found in this file.
• castle/castle_food.bin: Food resources data
• castle/castle_gemstone.bin: Gemstone resources data
• face/FaceData.bin: All data of character portrait. This data is used in FEITS.
• All file in asset folder: All assets.

• fst.bin: Store the list of files in the DLC.