Nestopia UE - RetroBIOS¶
Technical notes
Nestopia UE is a cycle-accurate NES/Famicom emulator. The libretro port tracks the upstream Nestopia JG project. NES cartridge games need no BIOS. Famicom Disk System games require disksys.rom (8 KB FDS BIOS) in the system directory. The core validates the BIOS via CRC32 against two known dumps: standard Famicom (0x5E607DCF) and Twin Famicom (0x4DF24A6C). An unknown BIOS triggers a warning but still loads.
NstDatabase.xml is an optional game database for region autodetection, mapper selection, and 4-player adapter recognition. A copy is baked into the core binary (libretro/nstdatabase.hpp) as fallback. The upstream Nestopia JG requires this file; the libretro port makes it optional.
An optional custom palette file (custom.pal, 64 RGB triplets) overrides built-in palettes when the nestopia_palette core option is set to Custom. The libretro port embeds all named palettes (Royaltea, Smooth FBx, etc.) that the upstream loads from external .pal files.
Five Famicom games use external ADPCM audio samples placed in system/nestopia/samples/{game}/ as numbered .wav files. These originate from MAME sample ZIPs. Games function without them but miss some audio.
8 files | 1 required, 7 optional | 8 in repo, 0 missing | 2 with HLE fallback Categories: 3 BIOS, 5 game data
disksys.rom required in repo
FDS BIOS ROM
- System: nintendo-fds
- Size: 8.0 KB
- SHA1:
57fe1bdee955... - MD5:
ca30b50f880e... - Validation: crc32
- Source:
libretro/libretro.cpp:2111-2139,source/core/NstFds.cpp:57-127 - Platforms: batocera, emudeck, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
- Mapped at 0xE000-0xFFFF (8 KB). retro_load_game returns false if missing when loading .fds files. CRC32 checked: Famicom 0x5E607DCF, Twin Famicom 0x4DF24A6C.
NstDatabase.xml optional in repo HLE fallback
Nestopia game database for region and mapper autodetection
- System: nintendo-nes
- Source:
libretro/libretro.cpp:2063-2093,libretro/nstdatabase.hpp - Platforms: lakka, retroarch, retrodeck, retropie, romm
- XML database matching games by SHA1+CRC32. Used for region, mapper, mirroring, and 4-player adapter detection. Built-in fallback exists so this file is optional.
custom.pal optional in repo HLE fallback
External NES color palette
- System: nintendo-nes
- Size: 192 B
- Source:
libretro/libretro.cpp:2041-2062 - 64 RGB triplets (64 x 3 bytes = 192 bytes). Loaded unconditionally at startup; applied only when nestopia_palette core option is set to Custom. Falls back to built-in Royaltea palette. Multiple valid palettes exist so no canonical hash.
nestopia/samples/moepro/ optional in repo game_data
Moero Pro Yakyuu audio samples (16 .wav files, 00.wav-15.wav)
nestopia/samples/moepro88/ optional in repo game_data
Moero Pro Yakyuu '88 audio samples (20 .wav files, 00.wav-19.wav)
nestopia/samples/mptennis/ optional in repo game_data
Moero Pro Tennis audio samples (19 .wav files, 00.wav-18.wav)
nestopia/samples/terao/ optional in repo game_data
Terao no Dosukoi Oozumou audio samples (6 .wav files, 00.wav-05.wav)
nestopia/samples/ftaerobi/ optional in repo game_data
Aerobics Studio audio samples (8 .wav files, 00.wav-07.wav)
Generated on 2026-09-14T09:03:10Z