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How To: Manage BIOS and Firmware

BIOS and firmware act as the low-level software that initializes a system and ensures hardware operates correctly. In emulation, the correct BIOS/firmware is often essential for accurate system behavior and sometimes required for an emulator to run at all.

Directory structure

By default, BIOS and firmware files should be placed in the main BIOS directory or within its subfolders. Some components also require BIOS/firmware to be located alongside game ROMs.

Type Folder Comment
BIOS Folder retrodeck/bios Primary default location for all BIOS/firmware files
BIOS Subfolders retrodeck/bios/<subfolders> Used by some components that expect BIOS files in structured subdirectories
ROMS Subfolders retrodeck/roms/<subfolders> Used by some components that require BIOS/firmware files to be placed next to the games

Some systems provide additional or alternative valid paths. Refer to the component-specific guides for full path requirements.

System-Specific Instructions

Each component guide within this wiki includes detailed steps for installing the required BIOS or firmware. Always consult the relevant guide to ensure correct setup.

RetroDECK BIOS Checker List

RetroDECK includes an automated BIOS Checker based on the each components component_manifest.json file under the bios key.

Each entry most likely contains:

  • filename - The exact filename of the file.

  • md5 - The MD5 checksum string.

  • system - The target system or systems identifier in the ES-DE/RetroDECK structure that requires the file.

  • description - A brief explanation of what the BIOS file contains or why it's needed.

  • required - Indicates whether the BIOS is mandatory, optional, or if at least one file from a group is needed.

Typical values include:

Required - Needed for the games to run.
Required, for some <Country> games - Needed for country-specific games to run.
Required, at least one - At least one BIOS of this type must be present for games to run.
Optional - Not required for general functionality but may enable extra features.

  • paths (optional) - The location where the file should be placed if not in the default retrodeck/bios directory.

Examples

neogeo.zip:

    {
      "filename": "neogeo.zip",
      "md5": "00dad01abdbf8ea9e79ad2fe11bdb182",
      "system": "fbneo",
      "description": "Neo Geo BIOS",
      "required": "required",
      "paths": [
        "$rd_home_roms_path/neogeo",
        "$rd_home_roms_path/fbneo",
        "$rd_home_roms_path/arcade"
      ]
    },

panafz1j-kanji.bin

    {
      "filename": "panafz1j-kanji.bin",
      "md5": "c23fb5d5e6bb1c240d02cf968972be37",
      "system": "3do",
      "description": "Kanji font ROM for Panasonic FZ-1J - required for Japanese games",
      "required": "Required for some Japanese games."
    },

Can I help update the Lists?

Yes, you can help update the lists by submitting pull requests on our GitHub in the components repo. Follow the same structure to add more BIOS/Firmware or correct any mistakes.