DuckStation: BIOS not found — the legal way to add your PS1 BIOS

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Use DuckStation's built-in BIOS dumper (or its documented dump tool) to extract the BIOS from the PlayStation 1 or PlayStation 2 you own, then point DuckStation at the folder. This is the only legal and reliable fix for "No BIOS found."

1. Check DuckStation's official documentation. The DuckStation project (duckstation.org / GitHub) documents how to dump the BIOS from your hardware. The method differs slightly by console: PS1 users typically need a way to run homebrew on the console (or use a specific dump tool), while PS2 owners can dump the PS1 BIOS that is built into the PS2's hardware using a simpler process. Follow the instructions for whichever console you own.
2. What you will get. A successful dump produces a .bin file named after your console's model — for example SCPH5501.BIN (US PS1), SCPH5500.BIN (JP PS1), SCPH5502.BIN (EU PS1), or a PS2-sourced file like SCPH-70012.BIN. Capitalisation varies; DuckStation is not case-sensitive.
3. Create a dedicated BIOS folder anywhere on your PC (e.g. C:\Emulation\BIOS\) and copy the dumped file into it. Keep the filename as-is from the dump — do not rename it.
4. Tell DuckStation where the folder is. In DuckStation, go to Settings → BIOS (or Settings → General → BIOS Directory depending on version). Browse to the folder you created. DuckStation will scan it automatically and show the detected BIOS entries. Select the one matching your console region and click OK.
5. Launch any PS1 game. The game should now boot normally, showing the PlayStation startup screen (or going straight into the game in fast-boot mode).

If DuckStation still says no BIOS found after placing the file, continue to S2 for path and format troubleshooting.

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You put the BIOS file in a folder and pointed DuckStation at it, but the BIOS list still appears empty or the game still fails — almost always a wrong path setting, a compressed file that was never extracted, or a filename that DuckStation doesn't recognise.

1. Make sure the file is extracted — not a zip or 7z archive. Enable file extensions in Windows Explorer. The BIOS must be a raw .bin file, not SCPH5501.BIN.zip or similar. If you see an archive, extract it first; the .bin inside is what DuckStation needs.
2. Point DuckStation at the folder, not the file. DuckStation's BIOS setting takes a directory path, not the path to the individual file. If you accidentally selected the file itself or a parent folder that is one level too high, DuckStation won't find anything. Set the path to the exact folder that contains the .bin file.
3. Click "Refresh" or restart DuckStation after changing the path. The BIOS scan does not always update live. Close and reopen the Settings dialog or use the Refresh button if your version has one.
4. Check file size. A valid PS1 BIOS file is exactly 512 KB (524,288 bytes). If your file is smaller or much larger, the dump failed or the file is corrupt. Redo the dump.

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DuckStation shows multiple BIOS files (or you dumped from both a PS1 and PS2) and you're not sure which one to use — pick the region that matches your games, but any valid BIOS will boot most titles.

1. Match region to your game library when possible. US/NTSC games work best with a US BIOS (SCPH5501-class), EU/PAL games with a PAL BIOS (SCPH5502-class), and JP games with a JP BIOS (SCPH5500-class). Most games boot on any region BIOS, but a mismatched region can cause timing differences or audio pitch issues on some PAL titles.
2. PS2-sourced BIOS files work. If you dumped from a PS2 you own, the resulting BIOS is fully compatible with DuckStation for PS1 games. The PS2's PS1-mode BIOS is slightly different from a PS1's native BIOS but both are well-supported.
3. DuckStation has a per-game BIOS override. In the game's properties (right-click a game in the list → Properties → Game Settings), you can pin a specific BIOS to that title. Use this if a particular game misbehaves on the global BIOS but works on a different one you dumped.