Getting started - RetroBIOS¶

What are BIOS files?¶

BIOS files are firmware dumps from original console hardware. Emulators need them to boot games for systems that relied on built-in software (PlayStation, Saturn, Dreamcast, etc.). Without the correct BIOS, the emulator either refuses to start the game or falls back to less accurate software emulation.

Installation¶

Three ways to get BIOS files in place, from easiest to most manual.

Option 1: the installer (recommended)¶

One command, nothing to clone. The bootstrap verifies install.py against the SHA-256 embedded in it, then the installer detects the platform and its BIOS directory, downloads only what is missing or incorrect, checks size and SHA-256/SHA-1 before writing, and installs each file atomically.

# Linux / macOS / Steam Deck
curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh | sh

# Windows (PowerShell)
irm https://raw.githubusercontent.com/Abdess/retrobios/main/install.ps1 | iex

Running install.py directly works the same way and needs nothing beyond Python 3.10+:

python install.py

Override detection when needed:

python install.py --platform retroarch --dest ~/custom/bios
python install.py --target switch      # keep only files for that hardware
python install.py --check              # verify existing files, download nothing
python install.py --list-platforms     # supported platforms and what was detected
python install.py --list-targets       # hardware targets for a platform
python install.py --jobs 4             # parallel downloads (default 8)
python install.py --verbose
python install.py --standalone-copies  # opt in to extra standalone-emulator paths

The default flow writes inside the detected platform tree only. Copies into separate standalone-emulator directories are opt-in, so discovery cannot cause unexpected writes elsewhere on the machine. Entries the collection cannot satisfy are reported as safely omitted and the run continues; the installer never substitutes a same-named file for one a hash-verifying platform would reject.

Arguments pass through the one-liner too, which is how you target an SD card mounted on another machine:

curl -fsSL https://raw.githubusercontent.com/Abdess/retrobios/main/install.sh \
  | sh -s -- --platform retroarch --dest /path/to/sdcard

Option 2: download.sh (Linux/macOS, from a clone)¶

Downloads a whole pack rather than the missing files. Needs curl and unzip:

bash scripts/download.sh retroarch ~/RetroArch/system/
bash scripts/download.sh --list  # show available packs

Option 3: manual download¶

Go to the releases page
Download the ZIP pack for your platform
Extract to the BIOS directory listed below

Packs over 2 GB are split into numbered volumes (.zip.001, .zip.002). Download every part and open the .001 file with 7-Zip or PeaZip, which extracts the whole set. See Download for the pack variants and per-setup instructions.

BIOS directory by platform¶

RetroArch¶

RetroArch uses the system_directory setting in retroarch.cfg. Default locations:

OS	Default path
Windows (installer)	`%APPDATA%\RetroArch\system\`
Windows (portable .7z)	`system\` next to `retroarch.exe`
Linux	`~/.config/retroarch/system/`
Linux (Flatpak)	`~/.var/app/org.libretro.RetroArch/config/retroarch/system/`
macOS	`~/Library/Application Support/RetroArch/system/`
Steam Deck (Flatpak)	`~/.var/app/org.libretro.RetroArch/config/retroarch/system/`
Android	`/storage/emulated/0/RetroArch/system/`

Windows has two layouts because the installer stores its data under %APPDATA% while the portable archive keeps everything inside the folder you extracted it to. If both exist on the machine, the one RetroArch actually reads is the one shown in the UI.

To check your actual path: open RetroArch, go to Settings > Directory > System/BIOS, or look for system_directory in retroarch.cfg.

Batocera¶

/userdata/bios/

Accessible via network share at \\BATOCERA\share\bios\ (Windows) or smb://batocera/share/bios/ (macOS/Linux).

Recalbox¶

/recalbox/share/bios/

Accessible via network share at \\RECALBOX\share\bios\.

RetroBat¶

bios/

Relative to the RetroBat installation directory (e.g., C:\RetroBat\bios\).

RetroDECK¶

~/retrodeck/bios/

On a MicroSD install the root moves, e.g. /run/media/mmcblk0p1/retrodeck/bios/.

The RetroDECK pack is the exception to "extract into the BIOS directory": its entries already start with bios/ (and one with roms/), so extract it into ~/retrodeck/ and the files land in the right place. Extracting into ~/retrodeck/bios/ would create ~/retrodeck/bios/bios/.

EmuDeck¶

Emulation/bios/

Located inside your Emulation folder. On Steam Deck, typically ~/Emulation/bios/.

Lakka¶

/storage/system/

Accessible via SSH or Samba.

RetroPie¶

~/RetroPie/BIOS/

RetroPie is archived in this project: its configuration is kept and packs are still built, but the upstream data is no longer scraped on a schedule. It inherits RetroArch's file set, so the RetroArch pack applies as well.

ROCKNIX¶

/storage/roms/bios/

Accessible via SSH or Samba, like Lakka.

MiSTer FPGA¶

/media/fat/games/

Files go under the per-core subdirectory the MiSTer BIOS database declares (e.g. /media/fat/games/3DO/boot.rom). Only the entries the BIOS database lists with a download URL are in scope: the rest ship with the MiSTer distribution and install themselves.

BizHawk¶

Firmware/

Relative to the BizHawk installation directory.

RomM¶

BIOS files live in the RomM library under bios/{platform_slug}/, one subfolder per system, and are managed through the web interface. Check the RomM documentation for setup details.

Verifying your setup¶

install.py --check verifies an existing install without downloading anything. For the full report, run verify.py from a clone of the repository:

python scripts/verify.py --platform retroarch
python scripts/verify.py --platform batocera
python scripts/verify.py --platform recalbox

The output shows each expected file with its status: ok, missing, or untested. untested means the file is there but its hash is not the expected one, which is how a wrong revision or a bad dump shows up.

Only hash-checking platforms can catch a wrong version: Batocera, RetroBat, Recalbox, EmuDeck, RetroDECK, RomM, ROCKNIX and MiSTer FPGA compare MD5, BizHawk compares SHA1. RetroArch, Lakka and RetroPie only check that the file exists, so add --verbose there to compare against the emulator ground truth.

For a single system:

python scripts/verify.py --system sony-playstation

For a single emulator core:

python scripts/verify.py --emulator beetle_psx

See Tools for the full CLI reference.

Next steps¶

FAQ - common questions and troubleshooting
Tools - all available scripts and options
Architecture - how the project works internally