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RetroBIOS

Geolith

Geolith emulates SNK Neo Geo MVS, SNK Neo Geo AES and SNK Neo Geo CD. It reads 23 files, 11 of them required: without a required file it does not start games. A required file is needed only by the machines that use it. Each file below cites the line of source code that reads it.

About this profile
Detail Value
Type libretro
Classification Official port
Source https://github.com/libretro/geolith-libretro
Upstream https://gitlab.com/jgemu/geolith
Version 0.5.0, stated in libretro/libretro.c
Revision libretro/geolith-libretro@2dc88e3fa72f, jgemu/geolith@05ddef568212
Profiled 2026-08-07
Profile YAML, JSON
Cores geolith
Systems SNK Neo Geo MVS, SNK Neo Geo AES, SNK Neo Geo CD
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 geolith
Technical notes

Geolith emulates the Neo Geo AES, MVS, CD, and CDZ. Cartridge systems use .NEO format ROMs, CD systems use .cue or .chd disc images. System ROMs come from MAME-format ZIP archives in the system directory.

Cartridge content opens aes.zip (System Type = AES, default) or neogeo.zip (MVS and Universe BIOS) (libretro/libretro.c:1222-1225). CD content opens neocd.zip (Front/Top Loader) or neocdz.zip (CDZ, default, and CD Universe BIOS) (libretro/libretro.c:1213-1221). Front/Top Loader additionally reads 000-lo.lo from neocdz.zip, so neocdz.zip is needed in every CD mode (libretro/libretro.c:1232-1239). The Irritating Maze in MVS mode loads 236-bios.sp1 from irrmaze.zip for trackball support. Without it the game runs but the trackball does not work (libretro/libretro.c:1281-1292).

Inside the opened archive, members are extracted by exact filename (src/geo.c:174-271). One 68K BIOS is selected by system type and region (defaults: System Type AES, Region USA):

  • AES Japan: neo-po.bin
  • AES other regions: neo-epo.bin
  • MVS USA: sp-u2.sp1
  • MVS Japan: japan-j3.bin
  • MVS Asia: sp-45.sp1
  • MVS Europe: sp-s2.sp1
  • Universe BIOS: uni-bios_4_0.rom
  • CD Front Loader: front-sp1.bin
  • CD Top Loader: top-sp1.bin
  • CDZ: neocd.bin
  • CD Universe BIOS: uni-bioscd33.rom 000-lo.lo is required in every mode. Only the Front/Top Loader tolerates its absence from neocd.zip because it comes from neocdz.zip instead (src/geo.c:234-243, 273-285). sfix.sfix and sm1.sm1 are required for MVS and Universe BIOS modes only (src/geo.c:245-267).

The core performs no hash or size validation on System ROMs. CD BIOS family detection and the optional CD speed hack patches use byte patterns and apply only when the 68K BIOS is at least 512 KiB (src/geo_cd.c:1888-1910, 1904-1924). Upstream declares the expected archive MD5s through the Jolly Good API BIOS list (jg.c:220-231), and the md5 fields on the archives below are copied from it.

Files

Section titled “Files”

23 files: 11 required, 12 optional.

In this collection: 23 in repo and 0 missing.

Required

Section titled “Required”
FileStatusHash

aes.zip

  • System: SNK Neo Geo AES
  • Neo Geo AES System ROMs. Opened when System Type is AES (default).
Hashes and source
required for SNK Neo Geo AES in repoMD5 ad9585c72130

neogeo.zip

  • System: SNK Neo Geo MVS
  • Neo Geo MVS System ROMs. Opened for MVS and Universe BIOS modes.
Hashes and source
required for SNK Neo Geo MVS in repoMD5 00dad01abdbf

neocdz.zip

  • System: SNK Neo Geo CD
  • Neo Geo CDZ System ROMs. Opened for CDZ (default) and CD Universe BIOS, and also supplies 000-lo.lo to Front/Top Loader mode.
Hashes and source
required for SNK Neo Geo CD in repoMD5 b31a246b6949

neo-epo.bin

  • System: SNK Neo Geo AES
  • AES 68K BIOS, non-Japan regions. Default for Region USA.
Hashes and source
  • CRC32: d27a71f1
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:178-181 (emulator code, libretro port)
required for SNK Neo Geo AES in repo in aes.zipCRC32 d27a71f1

000-lo.lo

Hashes and source
  • CRC32: 5a86cff2
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:234-243 (emulator code, libretro port)
required for SNK Neo Geo AES in repo in aes.zipCRC32 5a86cff2

sp-u2.sp1

Hashes and source
  • CRC32: e72943de
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:183-198 (emulator code, libretro port)
required for SNK Neo Geo MVS in repo in neogeo.zipCRC32 e72943de

000-lo.lo

Hashes and source
  • CRC32: 5a86cff2
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:234-243 (emulator code, libretro port)
required for SNK Neo Geo MVS in repo in neogeo.zipCRC32 5a86cff2

sfix.sfix

  • System: SNK Neo Geo MVS
  • System FIX layer tiles. Loaded for MVS and Universe BIOS modes.
Hashes and source
  • CRC32: c2ea0cfd
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:245-255 (emulator code, libretro port)
required for SNK Neo Geo MVS in repo in neogeo.zipCRC32 c2ea0cfd

sm1.sm1

  • System: SNK Neo Geo MVS
  • Z80 sound BIOS. Loaded for MVS and Universe BIOS modes.
Hashes and source
  • CRC32: 94416d67
  • Asked for by: upstream emulator
  • Source: src/geo.c:257-267 (upstream emulator)
required for SNK Neo Geo MVS in repo in neogeo.zipCRC32 94416d67

neocd.bin

  • System: SNK Neo Geo CD
  • Neo Geo CDZ 68K BIOS. Default for CD content.
Source
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:212-215 (emulator code, libretro port)
required for SNK Neo Geo CD in repo in neocdz.zip-

000-lo.lo

  • System: SNK Neo Geo CD
  • Zoom lookup table. Read from neocdz.zip in every CD mode, including Front/Top Loader.
Hashes and source
required for SNK Neo Geo CD in repo in neocdz.zipCRC32 5a86cff2

Optional

Section titled “Optional”
FileStatusHash

neocd.zip

  • System: SNK Neo Geo CD
  • Neo Geo CD Front/Top Loader System ROMs. Opened only when CD System is front or top loader.
Hashes and source
in repoMD5 006a881532f2

irrmaze.zip

  • System: SNK Neo Geo MVS
  • The Irritating Maze auxiliary BIOS. Loaded in MVS mode for trackball support. On failure the game runs without trackball.
Hashes and source
in repoMD5 0e369df30a70

neo-po.bin

Hashes and source
  • CRC32: 16d0c132
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:178-181 (emulator code, libretro port)
in repo in aes.zipCRC32 16d0c132

japan-j3.bin

Hashes and source
  • CRC32: dff6d41f
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:183-198 (emulator code, libretro port)
in repo in neogeo.zipCRC32 dff6d41f

sp-45.sp1

Hashes and source
  • CRC32: 03cc9f6a
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:183-198 (emulator code, libretro port)
in repo in neogeo.zipCRC32 03cc9f6a

sp-s2.sp1

Hashes and source
  • CRC32: 9036d879
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:183-198 (emulator code, libretro port)
in repo in neogeo.zipCRC32 9036d879

uni-bios_4_0.rom

  • System: SNK Neo Geo MVS
  • Universe BIOS 4.0, loaded when System Type is Universe BIOS. Emulated hardware type set by the geolith_unibios_hw option.
Hashes and source
  • CRC32: a7aab458
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:200-203 (emulator code, libretro port)
in repo in neogeo.zipCRC32 a7aab458

front-sp1.bin

Source
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:204-207 (emulator code, libretro port)
in repo in neocd.zip-

top-sp1.bin

Source
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:208-211 (emulator code, libretro port)
in repo in neocd.zip-

000-lo.lo

  • System: SNK Neo Geo CD
  • Zoom lookup table. Extraction is attempted but absence is tolerated in Front/Top Loader mode, where the copy in neocdz.zip is used instead.
Hashes and source
  • CRC32: 5a86cff2
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:234-243 (emulator code, libretro port)
in repo in neocd.zipCRC32 5a86cff2

uni-bioscd33.rom

  • System: SNK Neo Geo CD
  • Universe BIOS CD 3.3, loaded when CD System is CD Universe BIOS.
Source
  • Asked for by: emulator code, libretro port
  • Source: src/geo.c:216-219 (emulator code, libretro port)
in repo in neocdz.zip-

236-bios.sp1

  • System: SNK Neo Geo MVS
  • The Irritating Maze auxiliary 68K BIOS, replaces the MVS BIOS to enable trackball input.
Source
in repo in irrmaze.zip-

Next steps

Section titled “Next steps”
.

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.