beetle_saturn - RetroBIOS

Type	libretro
Classification	Community forks
Source	https://github.com/libretro/beetle-saturn-libretro
Upstream	https://mednafen.github.io/
Version	v0.9.45.1
Profiled	2026-03-24
Cores	mednafen_saturn, beetle-saturn
Systems	sega-saturn
Core ID	mednafen_saturn_libretro

Technical notes

Libretro port of Mednafen's Saturn emulation module, frozen circa v0.9.45.1 (2017) with some later backports. Region auto-detection reads the disc header and selects the matching BIOS. Manual override via beetle_saturn_region option.

InitCommon() returns false if the BIOS file is missing or not exactly 512 KB. Both region BIOS files are required for full region coverage.

KOF95 and Ultraman ROM carts are loaded when the cart type is set via core option or auto-detected from the internal game database.

Upstream Mednafen (1.32.x) has ST-V arcade board support (3 additional BIOS files) and bootable ROM cart support, both absent from this libretro port.

5 files | 2 required, 3 optional | 4 in repo, 1 missing

sega_101.bin required in repo japan, asia-ntsc

• System: sega-saturn
• Size: 512.0 KB
• Validation: size
• Source: mednafen/ss/ss.c:1761, mednafen/ss/ss.c:1786-1903
• Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
• Saturn BIOS v1.01 (Japan). Used when region is JP or Asia NTSC.

mpr-17933.bin required in repo north-america, europe, south-korea, asia-pal, brazil, latin-america

• System: sega-saturn
• Size: 512.0 KB
• Validation: size
• Source: mednafen/ss/ss.c:1763, mednafen/ss/ss.c:1786-1903
• Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
• Saturn BIOS (NA/EU). Used for all non-JP/Asia-NTSC regions.

mpr-18811-mx.ic1 optional in repo

• System: sega-saturn
• Size: 2.0 MB
• Source: mednafen/ss/cart.c:200-215, mednafen/ss/cart/rom.c:51
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
• KOF95 expansion ROM cart. Loaded when cart type set to KOF95.

mpr-19367-mx.ic1 optional in repo

• System: sega-saturn
• Size: 2.0 MB
• Source: mednafen/ss/cart.c:200-215, mednafen/ss/cart/rom.c:51
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
• Ultraman expansion ROM cart. Loaded when cart type set to Ultraman.

satar4mp.bin optional missing

• System: sega-saturn
• Size: 256.0 KB
• Source: mednafen/ss/cart.c:218, mednafen/ss/cart/ar4mp.c:150
• Action Replay 4M Plus firmware. Unfinished in source (mednafen/ss/cart/ar4mp.c:22-24), needs CPU UBC emulation. Cart type not exposed in core options.

Generated on 2026-09-14T09:03:09Z