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# Kronos - RetroBIOS

Type | libretro
Classification | official_port
Source | https://github.com/libretro/yabause
Upstream | https://github.com/FCare/Kronos
Version | v2.6.0
Profiled | 2026-03-24
Cores | kronos
Systems | sega-saturn, sega-stv

Technical notes

Kronos is a Sega Saturn and ST-V arcade emulator by FCare, forked from Yabause. Requires OpenGL 4.3 compute shaders.

Saturn BIOS search order: 1. {system}/kronos/saturn_bios.bin 2. {system}/saturn_bios.bin 3. {system}/sega_101.bin 4. {system}/mpr-17933.bin First file found wins. Real BIOS required (HLE deprecated, only available via kronos_force_hle_bios core option for debugging).

ST-V BIOS: {system}/kronos/stvbios.zip or {system}/stvbios.zip MAME-style ZIP containing region-specific EPROMs. Kronos picks the best match by game region and kronos_stv_favorite_region core option (EU/US/JP/TW).

ROM cartridges for KOF95 and Ultraman are auto-detected via game database (db.c) and loaded from system_dir when the corresponding game is running.

BIOS loading: libretro.c retro_load_game() lines 1601-1727. STV blob table: ctrl/src/stv.c BiosList lines 112-136. ROM cartridge DB: utils/src/db.c lines 43-45.

Standalone supports MPEG card ROM loading (Video CD card); disabled in libretro port (mpegpath = NULL in libretro.c:1578).

20 files | 2 required, 18 optional | 6 in repo, 14 missing

`saturn_bios.bin` -required

- System: sega-saturn
- Size: 512.0 KB
- Validation: size
- Source: `libretro.c:1619-1623`
- Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Primary Saturn BIOS. Any region accepted. Searched in kronos/ subdir first.

`sega_101.bin` -optional, japan

- System: sega-saturn
- Size: 512.0 KB
- Validation: size
- Source: `libretro.c:1627`
- Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Saturn BIOS v1.01 (Japan). Fallback if saturn_bios.bin missing.

`mpr-17933.bin` -optional, north-america, europe

- System: sega-saturn
- Size: 512.0 KB
- Validation: size
- Source: `libretro.c:1631`
- Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Saturn BIOS (NA/EU). Last fallback for Saturn mode.

`stvbios.zip` -required

- System: sega-stv
- Source: `libretro.c:1608-1617, ctrl/src/stv.c:112-136`
- Platforms: lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- MAME-style ZIP containing ST-V region BIOS EPROMs. Searched in kronos/ subdir first.

`epr-23603.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `f688ae60`
- Validation: crc32
- Source: `stv.c:120`

`epr-20091.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `59ed40f4`
- Validation: crc32
- Source: `stv.c:121`

`epr-19730.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `d0e0889d`
- Validation: crc32
- Source: `stv.c:122`

`epr-17951a.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `2672f9d8`
- Validation: crc32
- Source: `stv.c:123`

`epr-17740a.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `3e23c81f`
- Validation: crc32
- Source: `stv.c:124`

`epr-17740.ic8` -optional, japan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `5c5aa63d`
- Validation: crc32
- Source: `stv.c:125`

`epr-17954a.ic8` -optional, europe, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `f7722da3`
- Validation: crc32
- Source: `stv.c:126`

`epr-17952a.ic8` -optional, north-america, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `d1be2adf`
- Validation: crc32
- Source: `stv.c:127`

`epr-17741a.ic8` -optional, north-america, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `4166c663`
- Validation: crc32
- Source: `stv.c:128`

`epr-19854.ic8` -optional, taiwan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `e09d1f60`
- Validation: crc32
- Source: `stv.c:129`

`epr-17953a.ic8` -optional, taiwan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `a4c47570`
- Validation: crc32
- Source: `stv.c:130`

`epr-17742a.ic8` -optional, taiwan, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `02daf123`
- Validation: crc32
- Source: `stv.c:131`

`stv110.bin` -optional, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `3dfeda92`
- Validation: crc32
- Source: `stv.c:132`

`stv1061.bin` -optional, in `stvbios.zip`, missing from repo

- System: sega-stv
- Size: 512.0 KB
- CRC32: `728dbca3`
- Validation: crc32
- Source: `stv.c:133`

`mpr-18811-mx.ic1` -optional

- System: sega-saturn
- Size: 2.0 MB
- Validation: size
- Source: `utils/src/db.c:43-44, sys/memory/src/cs0.c:1526-1544`
- Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- ROM cartridge for The King of Fighters '95. Auto-detected via game DB.

`mpr-19367-mx.ic1` -optional

- System: sega-saturn
- Size: 2.0 MB
- Validation: size
- Source: `utils/src/db.c:45, sys/memory/src/cs0.c:1526-1544`
- Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- ROM cartridge for Ultraman: Hikari no Kyojin Densetsu. Auto-detected via game DB.

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