Yet Another Gamecube Documentation

14 general File Formats

14.1 BNR (Banner file format)

this is the format of the file 'opening.bnr' (file size: always 6.496 bytes) found in the root directory of every Gamecube disc. This file is the little image that is displayed in the cube menu when inserting a disc into the gamecube, when in menu mode.

start	end	size	Description
`0x0000`	`0x0003`	`0x0004`	Magic Word "BNR1" (US/JP) or 'BNR2' (EU)
`0x0004`	`0x001f`		padding zeroes
`0x0020`	`0x181f`	`0x1800`	Graphical Data (Pixel-format is RGB5A1)
`0x1820`	`0x183f`	`0x0020`	Gamename (*)
`0x1840`	`0x185f`	`0x0020`	Company/Developer (*)
`0x1860`	`0x189f`	`0x0040`	Full Game Title (*)
`0x18a0`	`0x18df`	`0x0040`	Company/Developer Full name, or description (*)
`0x18e0`	`0x195f`	`0x0080`	Game Description (*)

(*) All Text is all stored in either SHIFT-JIS or ASCII, depending on the region of the Game.

note: In the filesystem of european Games with multi-lingual text there may be several .bnr files (opening.bnr, openingUS.bnr, openingEU.bnr, openingJP.bnr). The opening.bnr is a BNR2 file, it is just like a regular BNR file, except that the metadata at the end repeats several times in different languages. 0x1820 through 0x1960 are the first, and it continues in blocks of 0x0140.

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14.2 DOL (Gamecube Executable)

This is a custom GameCube program file format, which is directly booted by GameCubes' BIOS (to be exact, by the apploader on retail discs. a different apploader could well load a binary in whatever different format.).

start	end	size	description
`0x0000`	`0x001B`		Text[0..6] sections File Positions
`0x001C`	`0x0047`		Data[0..10] sections File Positions
`0x0048`	`0x0063`		Text[0..6] sections Mem Address
`0x0064`	`0x008F`		Data[0..10] sections Mem Address
`0x0090`	`0x00AB`		Text[0..6] sections Sizes
`0x00AC`	`0x00D7`		Data[0..10] sections Sizes
`0x00D8`		`0x04`	BSS Mem address
`0x00DC`		`0x04`	BSS Size
`0x00E0`		`0x04`	Entry Point
`0x00e4`		`0x1c`	unused
`0x0100`			Start of sections data (body)

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14.3 ELF (Executable and linkable Format)

The ELF format is a standard, known format for debugging target specific code, etc. GCC targeted for the PPC 750 processor or even for the specialized Gekko processor has a final output of ELF format files. The exact GameCube ELF file format details are currently unknown, but they should be similar to the standard specification.

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14.4 GCB (QOOB Flash Files)

start end size description

0x00 0x03 4 ID, indicates whats in the block

`0x28432920`	'`(C)` ' - qoob bios file
`0x454c4600`	'`ELF0`' - ELF File
`0x42494e00`	(not yet) '`BIN0`'
`0x444f4c00`	(not yet) '`DOL0`'

0x04 0xf7 description, will be shown in boot menu (by the qoob bios)

0xf8 0xfb 4 reserved

0xfc 0xff 4 size of block

0x100 ... data

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14.5 GCM (Gamecube Disc Image)

These files are always 1.4GB's exactly and each contains a complete binary image of a proprietary format GameCube DVD. This file format is used for the NR-Writer DVD writing software which writes special DVDs that can only be read by NR-Reader GameCubes. The GCM file format can probably be closely compared to the ISO file format for CDs in its purpose.

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14.6 GCI (Gamecube Game Save)

Used by the EMS Memory Adapter.

64 byte header (equal to FST entry on memcard), followed by the file data (as on memory card)

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14.7 GCP (Gamecube Memorycard Image)

Used by the EMS Memory Adapter.

this is a raw image of all blocks of a memory card.

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14.8 TGC

a proprietary image format found on demo discs and eg the zelda n64 emu

note: there seem to be tgc files on european discs that follow a different layout (no header).

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14.8.1 Header

start	end	size	description
`0x0000`	`0x0003`	`0x0004`	TGC-Magic (`0xae0f38a2`)
`0x0004`	`0x0007`	`0x0004`	? (=`0x00000000`)
`0x0008`	`0x000b`	`0x0004`	TGC-Header Size (=`0x00008000`)
`0x000c`	`0x000f`	`0x0004`	? (=`0x00100000`)
`0x0010`	`0x0013`	`0x0004`	Offset to FST inside embedded GCM
`0x0014`	`0x0017`	`0x0004`	FST Size
`0x0018`	`0x001b`	`0x0004`	max FST Size
`0x001c`	`0x001f`	`0x0004`	Offset to Boot-DOL inside embedded GCM
`0x0020`	`0x0023`	`0x0004`	Boot-DOL Size
`0x0024`	`0x0027`	`0x0004`	?
`0x0028`	`0x002b`	`0x0004`	?
`0x002c`	`0x002f`	`0x0004`	Offset to Banner inside embedded GCM ?
`0x0030`	`0x0033`	`0x0004`	Banner Size ?
`0x0034`	`0x0037`	`0x0004`	?

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14.8.2 embedded GCM

usually starts at offset 0x00008000 (after the TGC Header) and follows exactly the same layout as a GCM file, with the following exceptions:

Boot-DOL offset, FST offset contain bogus data and must be substituted by the data found in the TGC header
offsets within the embedded GCM file must be calculated relative to the start of the embedded GCM (obviously)

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14.9 VGC (Viper Flash Files)

start end size description

0x00 0x03 4 Viper Magic ('VIPR')

0x04 1 Configuration Flags

bit(s)	description
7	GC_FLASH_ACCESS - allows access to the flashrom
6	?
5	?
4	?
3	COMMAND_MODE - enables modchip command mode (requires extended mode)
2	EXTENDED_MODE - allows reading of original IPL
1	COBRA_ENCRYPTION - enables additional encryption mode
0	DISABLE_CHIP - disables the modchip

0x05 1 Lid Sensor Status at Boot Time (*2)

0	LID_OPEN
1	LID_CLOSED
2	LID_PASSTHROUGH

0x06 0x0f 10 padding (zeros)

0x10 0x1f 16 BIOS Name in Ascii

0x20 ... Encrypted (*1) BIOS, loaded to 0x81300000

(*1) encrypted with the IPL XOR-Stream (*2) original docs state that the default value is 0xff, however actually using this value seems to cause problems.

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