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# Gearcoleco - RetroBIOS

Type | libretro
Classification | official_port
Source | https://github.com/drhelius/Gearcoleco
Version | 1.0.0
Profiled | 2026-03-23
Cores | gearcoleco
Systems | colecovision

Technical notes

ColecoVision emulator by Ignacio Sanchez (drhelius). Official port maintained by the upstream author. The ColecoVision BIOS ROM is required. Without it, the core renders a static placeholder image (kNoBiosImage from no_bios.h) and games do not execute.

The libretro wrapper (libretro.cpp:293-306) tries "colecovision.rom" first, then falls back to "coleco.rom". Both resolve to the same LoadBios() call in Memory.cpp:228-259 which validates size == 0x2000 (8192 bytes) only. No hash check is performed.

On reset, BIOS byte at offset 0x69 is patched for region selection: 0x3C for NTSC, 0x32 for PAL (Memory.cpp:184-187).

SGM (Super Game Module) expanded RAM requires no additional BIOS files.

1 files | 1 required, 0 optional | 1 in repo, 0 missing

`colecovision.rom` -required

- System: colecovision
- Size: 8.0 KB
- Aliases: `coleco.rom`
- Validation: size
- Source: `platforms/libretro/libretro.cpp:293-306, src/Memory.cpp:228-259`
- Platforms: batocera, emudeck, lakka, retroarch, retrobat, retrodeck, retropie

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