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RetroBIOS

IroGB

IroGB emulates Nintendo Game Boy and Nintendo Game Boy Color. It reads 2 files, none of them required: it starts games without them.

About this profile
Detail Value
Type libretro
Classification Official port
Source https://github.com/AlexSutila/IroGB
Version v1.0.0, stated in src/frontend/libretro/libretro_host.cpp
Revision AlexSutila/IroGB@7b6bb9b1f9cb
Profiled 2026-09-03
Profile YAML, JSON
Cores irogb
Systems Nintendo Game Boy, Nintendo Game Boy Color
Install this emulator's files

The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell
&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator irogb
Technical notes

IroGB is a Game Boy and Game Boy Color emulator by Alex Sutila. The libretro frontend lives in src/frontend/libretro of the same repository as the SDL3, raylib and Python frontends. The buildbot builds the repository default branch, release, with cmake -DBUILD_LIBRETRO=ON -DNO_CORE_FILESYSTEM=ON (.gitlab-ci.yml:10-14).

Boot ROMs are read from the root of the system directory (src/frontend/libretro/libretro_host.cpp:61-84). The irogb_bios core option picks the file: dmg opens dmg_boot.bin, cgb opens cgb_boot.bin, auto (the default) tries cgb_boot.bin then dmg_boot.bin, none opens nothing (src/frontend/libretro/libretro_host.cpp:86-113). Under auto a DMG cartridge boots through the CGB boot ROM whenever cgb_boot.bin is present and gets the CGB colouring of monochrome games. The irogb_monochrome_dmg option turns that off.

BootROM accepts a file of exactly 256 or 2304 bytes and rejects any other size (src/memory/boot.cpp:10-24). The size also picks the machine: a 2304-byte image starts in CGB mode (src/gbc.cpp:330-340). 256 bytes covers DMG, DMG0, MGB and SGB dumps, 2304 bytes CGB, CGB0, AGB0 and AGB dumps (includes/memory/boot.hpp:9-30). Only the two names above are ever opened. No hash is checked.

Without a boot ROM, or when the file fails to open or has another size, the core continues with skip_bios(), which loads post-boot CPU and MMIO values, unmaps the boot ROM and sets CGB mode from the cartridge header (src/gbc.cpp:342-349, src/gbc.cpp:387-405, src/gbc.cpp:489-490).

The .info declares cgb_bios.bin, but the code opens cgb_boot.bin.

Files

Section titled “Files”

2 files: 0 required, 2 optional. 2 have an HLE fallback.

In this collection: 2 in repo and 0 missing.

Optional

Section titled “Optional”

dmg_boot.bin optional in repo HLE fallback

Game Boy (DMG) boot ROM

  • System: Nintendo Game Boy
  • Opened with irogb_bios set to dmg, or to auto when cgb_boot.bin is absent.
Validation and source

cgb_boot.bin optional in repo HLE fallback

Game Boy Color (CGB) boot ROM

  • System: Nintendo Game Boy Color
  • Opened with irogb_bios set to cgb or auto. Under auto it also boots DMG cartridges in CGB mode.
Validation and source

Next steps

Section titled “Next steps”
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Maintained by Abdess on GitHub. Report a problem.

Packs from release v2026.10.10, .

MIT for the tooling and metadata. BIOS and firmware files are third-party system software, preserved for personal backup, archival and interoperability.