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RetroBIOS

What is a BIOS?

A console has a small program inside it. It starts first, then starts the game. This program is the BIOS, also called firmware.

Get your files

An emulator is an app that acts like a console. For many consoles, it needs a copy of the BIOS. That copy is a file: a BIOS file.

How a BIOS file is usedA device runs a setup, the setup starts an emulator, and the emulator reads BIOS files from one folder. The ZIP or the command fills that folder.1Your deviceA PC, a SteamDeck, a handheldor a TV box2SetupThe menu youpick a game from3EmulatorStarts the gameand reads itsBIOS4BIOS folderBatocera reads/userdata/bios/How a BIOS file is usedA device runs a setup, the setup starts an emulator, and the emulator reads BIOS files from one folder. The ZIP or the command fills that folder.1Your deviceA PC, a Steam Deck, a handheld or a TVbox2SetupThe menu you pick a game from3EmulatorStarts the game and reads its BIOS4BIOS folderBatocera reads/userdata/bios/
Setups: Batocera, EmuDeck, RetroArch and 15 more. Examples: Batocera starts DuckStation, EmuDeck starts PCSX2, RetroArch starts Beetle PSX. BIOS folders: Batocera /userdata/bios/, EmuDeck ~/Emulation/bios/, RetroArch system/. The ZIP or the command fills that folder.

How it works

Section titled “How it works”
  1. You pick a game in your setup's menu.
  2. The setup starts the emulator.
  3. The emulator opens the BIOS file in your BIOS folder.
  4. The game starts.

If step 3 fails, you see "BIOS missing" or a black screen.

Do I need one?

Section titled “Do I need one?”
  • Yes: PlayStation 1 and 2, Saturn, Neo Geo, PC Engine CD and many home computers.
  • Better with it: Dreamcast. Some games need it.
  • Usually not: NES, Super Nintendo, Mega Drive, Game Boy and Game Boy Advance.
  • Add-ons need their own: the Famicom Disk System and the Mega CD.

Details: Every console, one by one

The name must match

Section titled “The name must match”

Most emulators look for one exact name, like scph5501.bin. A file with another name is not found. A few, like DuckStation, read any name and check what the file holds.

The version must match

Section titled “The version must match”

Two files can have the same name and different contents. One may be for Japan, another for Europe.

Some setups check each file's hash, a fingerprint of its contents. Batocera, Recalbox and EmuDeck report a version they do not expect.

Our files are the versions each setup expects.

Can a game start without it?

Section titled “Can a game start without it?”

Sometimes. Some emulators carry their own code in place of the BIOS. Some games then glitch or do not start. The real file works best, so we include it.

Section titled “Is it legal?”

Laws differ by country. Is it legal?

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.