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# Boytacean - RetroBIOS

Type | standalone + libretro
Classification | official_port
Source | https://github.com/joamag/boytacean
Version | 0.11.5
Profiled | 2026-03-23
Cores | boytacean
Systems | nintendo-gb, nintendo-gbc

Technical notes

Game Boy / Game Boy Color emulator written in Rust by Joao Magalhaes.

Libretro: all boot ROMs compiled into binary as static byte arrays in src/data.rs. load_boot_static() copies from arrays. No filesystem access, no RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY. No external files. ref: core.rs:402 instance.load(true) -> gb.rs:1311 -> load_boot_static

Standalone (SDL): also defaults to embedded boot ROMs via load(true). User can override via --boot-rom-path CLI argument with any boot ROM file. load_boot_file() with hardcoded ./res/boot/*.bin paths exists in gb.rs:1361 but is not called from any frontend.

Boot ROM defaults: DmgBootix (DMG), CgbBoytacean (CGB) — open-source.

6 files | 0 required, 6 optional | 3 in repo, 3 missing | 6 with HLE fallback

`dmg_boot.bin` -optional, HLE available, standalone

- System: nintendo-gb
- Size: 256 B
- Source: `gb.rs:1350 load_boot_static, data.rs:14 DMG_BOOT`
- Platforms: lakka, recalbox, retroarch, retropie
- Original Nintendo DMG boot ROM

`sgb_boot.bin` -optional, HLE available, standalone

- System: nintendo-gb
- Size: 256 B
- Source: `gb.rs:1351 load_boot_static, data.rs:29 SGB_BOOT`
- Platforms: batocera, recalbox, retrobat
- Super Game Boy boot ROM

`dmg_bootix.bin` -optional, HLE available, standalone, missing from repo

- System: nintendo-gb
- Size: 256 B
- Source: `gb.rs:1352 load_boot_static, data.rs:44 DMG_BOOTIX`
- Open-source DMG boot ROM from Bootix (default DMG)

`mgb_bootix.bin` -optional, HLE available, standalone, missing from repo

- System: nintendo-gb
- Size: 256 B
- Source: `gb.rs:1353 load_boot_static, data.rs:59 MGB_BOOTIX`
- Open-source MGB (Pocket) boot ROM from Bootix

`cgb_boot.bin` -optional, HLE available, standalone

- System: nintendo-gbc
- Size: 2.2 KB
- Source: `gb.rs:1354 load_boot_static, data.rs:74 CGB_BOOT`
- Platforms: lakka, recalbox, retroarch, retropie
- Original Nintendo CGB boot ROM

`cgb_boytacean.bin` -optional, HLE available, standalone, missing from repo

- System: nintendo-gbc
- Size: 2.2 KB
- Source: `gb.rs:1355 load_boot_static, data.rs:177 CGB_BOYTACEAN`
- Custom open-source CGB boot ROM (default CGB)

Generated on 2026-03-25T14:56:43Z