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This is a collection of all known boot ROMs dumped from various Gameboy models.
These is the code that is responsible for displaying the scrolling Nintendo
logo on startup, playing the iconic po-ling sound, as well as verifying the
logo and header checksum in an attempt to lock out unlicensed cartridges.
They can be used in supported emulators to emulate the full boot process.
Normally, these ROMs are disabled when control is handed over to the game
cartridge, which makes dumping them difficult, but various methods have been
devised throughout the years to make dumping them possible.
The bootstraps are discussed further on the following GB Dev Wiki page:
dmg_rom.bin - The DMG boot ROM.
This is the most common version of the boot ROM found in the original DMG-01
model of Gameboy.
dmg0_rom.bin - Early DMG boot ROM with different behavior.
This is the very early variant of the DMG boot ROM which is only found in very
early Japan-sold DMG units. It has a different behavior in that it makes the
screen flash if the boot process fails, instead of scrolling down a
(potentially corrupted looking) logo and hanging.
mgb_boot.bin - The Pocket Gameboy boot ROM.
Only differs from dmg_rom.bin in one byte, which loads the value $FF into the
A register instead $01 just before handing over the control to the game. This
can be used by the game to detect that it is running on MGB hardware.
sgb_boot.bin - The Super Gameboy boot ROM.
Instead of showing a logo animation, this ROM sends the ROM header to the SNES
part of the Super Gameboy, which shows a fancy animation before displaying the
sgb2_boot.bin - The Super Gameboy 2 boot ROM.
Analogous to mgb_boot.bin, the SGB2 boot ROM only differs from the SGB boot
ROM in one byte loading a value into the A register which allows SGB2 hardware
to be distinguished from SGB hardware.
cgb_bios.bin - The Gameboy Color boot ROM
The GBC boot ROM is spread out over a bigger memory area than the original 256
bytes, and has slightly increased functionality compared previous boot ROMs,
including the ability to choose a palette from a number of presets for non-GBC
cgb0_bios.bin - Early Gameboy Color boot ROM
This early revision of the GBC boot ROM was dumped by Matt Currie in 2019 from
a CPU CGB (CPU with no suffix). It has the following differences from the
later more common version of the ROM:
- CGB0 does not initialize Wave RAM, newer revisions do.
- CGB0 uses less optimized code to load the Game Boy logo.
- CGB0 has two redundant writes to RAM, which were removed in newer revisions.
gamefighter_rom.bin - Boot ROM from the Gameboy clone Game Fighter.
fortune_rom.bin - Boot ROM from the Gameboy clone Fortune/Bitman 3000B.
These boot ROMs are dumped from two unlicensed Gameboy clones which each has a
rather different boot ROM compared to the originals.
Using these files with emulators
BGB has support for boot ROMs, which can be enabled by going to the system tab
in the settings, entering a path to the ROM in question, and checking "bootroms
Higan needs the SGB and/or SGB2 boot ROM for correctly running Super Gameboy
enhanced software. The SGB boot ROM in particular can't be emulated through HLE
(high level emulation) since it communicates with the SNES. Using these files
with Higan is documented here:
Mooneye-GB, an accuracy focused Gameboy emulator written by gekkio (the same
person mentioned in the history section) supports boot ROMs and in fact
requires them to guarantee cycle accurate emulation.
The first time anyone published a dump of such a ROM was in 2003 when neviksti
decapped a DMG CPU and manually read out each individual bit, all 2048 of them.
In 2009, the Super Gameboy and Gameboy Color boot ROMs were dumped by Costis
Sideris. The SGB boot ROM was dumped using an overclock attack, whereas the GBC
boot ROM was dumped using a power and clock glitch attack.
In 2014, BennVenn came up with a simple clock glitching method which requires
nothing but a piece of wire. The method consists of connecting one side of the
crystal oscillator circuit to ground briefly, which makes the CPU jump to a
random place in memory without disabling the boot ROM, which allows it to be
read out. By using this method, he was able to dump the MGB (Gameboy Pocket)
The same year nitro2k01 (the person running this site and writing this text)
dumped the boot ROM of two unlicensed Gameboy clones using BennVenn's method.
They have a slightly different behavior from the original ones and may be
partially or fully rewritten.
In 2015 gekkio, using another overclock attack, dumped the SGB2 boot ROM.
In 2016, gekkio also dumped an variant of the DMG boot ROM only found in very
early DMG units, now dubbed dmg0 in the world of Gameboy research.
The only known variant that has not yet been dumped is the GBA version of the
GBC boot ROM. Just like the MGB and SGB2 variants, the only change in the GBA
version of the GBC boot ROM seems to be that the CPU B register has a different
value to allow detection of GBA hardware.
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