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# Geolith - RetroBIOS

Type | libretro
Classification | official_port
Source | https://github.com/libretro/geolith-libretro
Upstream | https://gitlab.com/jgemu/geolith
Version | 0.3.0
Profiled | 2026-03-21
Cores | geolith
Systems | snk-neogeo-mvs, snk-neogeo-aes

Technical notes

Geolith is a highly accurate Neo Geo AES and MVS emulator using .NEO format ROMs only. BIOS files must be provided as MAME-format ZIP archives in the system directory. The core selects which ZIP to open based on the "geolith_system_type" core option (libretro/libretro.c:1017-1018): - AES mode -> aes.zip - MVS mode -> neogeo.zip - Uni mode -> neogeo.zip (loads uni-bios_4_0.rom from it)

Inside the ZIP, specific ROM files are extracted by filename (src/geo.c:162-241): 1. One 68K BIOS ROM, selected by system type + region: - AES Japan: neo-po.bin - AES other: neo-epo.bin - MVS US: sp-u2.sp1 - MVS Japan: japan-j3.bin - MVS Asia: sp-45.sp1 - MVS Europe: sp-s2.sp1 - Universe: uni-bios_4_0.rom 2. 000-lo.lo (zoom lookup table, always required) 3. sfix.sfix (FIX layer tiles, required for MVS/Uni, not AES) 4. sm1.sm1 (Z80 sound BIOS, required for MVS/Uni, not AES)

The AES mode only needs the 68K BIOS + 000-lo.lo. MVS and Universe BIOS modes additionally need sfix.sfix and sm1.sm1.

11 files | 6 required, 5 optional | 2 in repo, 9 missing

`sp-u2.sp1` -required, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `e72943de`
- Source: `src/geo.c:174`
- MVS USA ver. 5 (2 slot) - default for US region

`japan-j3.bin` -optional, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `dff6d41f`
- Source: `src/geo.c:177`
- MVS Japan (J3) - default for JP region

`sp-45.sp1` -optional, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 512.0 KB
- CRC32: `03cc9f6a`
- Source: `src/geo.c:180`
- NEO-MVH MV1C (Asia) - default for AS region

`sp-s2.sp1` -optional, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `9036d879`
- Source: `src/geo.c:183`
- MVS Asia/Europe ver. 5 (1 slot) - default for EU region

`uni-bios_4_0.rom` -optional, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `a7aab458`
- Source: `src/geo.c:189`
- Universe BIOS ver. 4.0 - only version supported by Geolith

`000-lo.lo` -required, in `neogeo.zip`

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `5a86cff2`
- Source: `src/geo.c:207-208`
- Platforms: lakka, recalbox, retroarch, retrodeck, retropie
- Zoom lookup table (vertical shrink ROM)

`sfix.sfix` -required, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `c2ea0cfd`
- Source: `src/geo.c:218-219`
- System FIX layer tiles (text layer)

`sm1.sm1` -required, in `neogeo.zip`, missing from repo

- System: snk-neogeo-mvs
- Size: 128.0 KB
- CRC32: `94416d67`
- Source: `src/geo.c:229-230`
- Z80 sound BIOS

`neo-epo.bin` -required, in `aes.zip`, missing from repo

- System: snk-neogeo-aes
- Size: 128.0 KB
- CRC32: `d27a71f1`
- Source: `src/geo.c:168`
- AES Asia/US/EU - default for non-JP regions

`neo-po.bin` -optional, in `aes.zip`, missing from repo

- System: snk-neogeo-aes
- Size: 128.0 KB
- CRC32: `16d0c132`
- Source: `src/geo.c:167-168`
- AES Japan - default for JP region

`000-lo.lo` -required, in `aes.zip`

- System: snk-neogeo-aes
- Size: 128.0 KB
- CRC32: `5a86cff2`
- Source: `src/geo.c:207-208`
- Platforms: lakka, recalbox, retroarch, retrodeck, retropie
- Zoom lookup table (same ROM as in neogeo.zip)

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