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# mesen-s - RetroBIOS

Type | libretro
Classification | official_port
Source | https://github.com/libretro/Mesen-S
Upstream | https://github.com/SourMesen/Mesen-S
Version | 0.4.0
Profiled | 2026-03-24
Cores | mesen-s
Systems | nintendo-snes, nintendo-gb, nintendo-gbc, nintendo-super-game-boy, nintendo-satellaview

Technical notes

High-accuracy SNES/SFC emulator with Game Boy/Color and Super Game Boy support. Upstream archived at 0.4.0, superseded by Mesen2. DSP firmware can be loaded as combined files (dsp1.rom, dsp1b.rom, dsp2.rom, dsp3.rom, dsp4.rom, st010.rom, st011.rom) or split program/data ROMs. Combined files are tried first, size validated. HLE coprocessor option available for DSP-1/DSP-1B only (libretro core option mesen-s_hle_coprocessor). CX4 is fully HLE, no firmware needed. ST018 detected but not emulated. GB/GBC/SGB boot ROMs fall back to embedded open-source SameBoy boot ROMs when external files are not found.

21 files | 0 required, 21 optional | 21 in repo, 0 missing | 8 with HLE fallback

`dsp1.program.rom` -optional, HLE available

- Size: 6.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:95, Core/FirmwareHelper.h:17-35`
- Platforms: lakka, retroarch, retropie
- DSP-1 program ROM. HLE fallback in libretro port only

`dsp1.data.rom` -optional, HLE available

- Size: 2.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:95, Core/FirmwareHelper.h:17-35`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-1 data ROM

`dsp1b.program.rom` -optional, HLE available

- Size: 6.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:96`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-1B program ROM. HLE fallback in libretro port only

`dsp1b.data.rom` -optional, HLE available

- Size: 2.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:96`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-1B data ROM

`dsp2.program.rom` -optional

- Size: 6.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:97`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-2 program ROM

`dsp2.data.rom` -optional

- Size: 2.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:97`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-2 data ROM

`dsp3.program.rom` -optional

- Size: 6.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:98`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-3 program ROM

`dsp3.data.rom` -optional

- Size: 2.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:98`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-3 data ROM

`dsp4.program.rom` -optional

- Size: 6.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:99`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-4 program ROM

`dsp4.data.rom` -optional

- Size: 2.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:99`
- Platforms: lakka, retroarch, retrodeck, retropie
- DSP-4 data ROM

`st010.program.rom` -optional

- Size: 48.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:100`
- Platforms: lakka, retroarch, retrodeck, retropie
- ST-010 program ROM

`st010.data.rom` -optional

- Size: 4.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:100`
- Platforms: lakka, retroarch, retrodeck, retropie
- ST-010 data ROM

`st011.program.rom` -optional

- Size: 48.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:101`
- Platforms: lakka, retroarch, retrodeck, retropie
- ST-011 program ROM

`st011.data.rom` -optional

- Size: 4.0 KB
- Validation: size
- Source: `Core/NecDsp.cpp:101`
- Platforms: lakka, retroarch, retrodeck, retropie
- ST-011 data ROM

`dmg_boot.bin` -optional, HLE available

- Size: 256 B
- Aliases: `gb_bios.bin`
- Validation: size
- Source: `Core/FirmwareHelper.h:148, Core/Gameboy.cpp:108-114, Core/GbBootRom.h:6`
- Platforms: lakka, recalbox, retroarch, retropie
- Game Boy (DMG) boot ROM. Falls back to embedded SameBoy open-source boot ROM

`cgb_boot.bin` -optional, HLE available

- Size: 2.2 KB
- Aliases: `gbc_bios.bin`
- Validation: size
- Source: `Core/FirmwareHelper.h:149, Core/Gameboy.cpp:108-119, Core/GbBootRom.h:6`
- Platforms: lakka, recalbox, retroarch, retropie
- Game Boy Color boot ROM. Falls back to embedded SameBoy open-source boot ROM

`sgb_boot.bin` -optional, HLE available

- Size: 256 B
- Aliases: `sgb_bios.bin`
- Validation: size
- Source: `Core/FirmwareHelper.h:150, Core/Gameboy.cpp:108-127, Core/GbBootRom.h:6`
- Platforms: batocera, recalbox, retrobat
- Super Game Boy boot ROM for GB CPU. Falls back to embedded SameBoy open-source boot ROM

`sgb2_boot.bin` -optional, HLE available

- Size: 256 B
- Aliases: `sgb_bios.bin`
- Validation: size
- Source: `Core/FirmwareHelper.h:151, Core/Gameboy.cpp:108-127, Core/GbBootRom.h:6`
- Platforms: batocera, recalbox, retrobat, retrodeck
- Super Game Boy 2 boot ROM for GB CPU. Falls back to embedded SameBoy open-source boot ROM

`SGB1.sfc` -optional

- Size: 256.0 KB
- Validation: size
- Source: `Core/FirmwareHelper.h:118-133, Core/BaseCartridge.cpp:630-638`
- Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Super Game Boy SNES cartridge ROM. Without it, SGB mode falls back to regular GB

`SGB2.sfc` -optional

- Size: 512.0 KB
- Validation: size
- Source: `Core/FirmwareHelper.h:118-133, Core/BaseCartridge.cpp:630-638`
- Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Super Game Boy 2 SNES cartridge ROM. Core option mesen-s_sgb2 selects SGB version

`BS-X.bin` -optional

- Size: 1.0 MB
- Validation: size
- Source: `Core/FirmwareHelper.h:39-47,96-113, Core/BaseCartridge.cpp:65`
- Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Satellaview BS-X BIOS ROM. Minimum accepted size is 32768 bytes

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