PS1 BIOS Not Working

Fix 1: Check the BIOS directory path

Go to Settings → BIOS. The "BIOS Directory" field must point to the folder containing your .bin file. Click "Browse" and navigate to the correct location.

Default paths: Documents\DuckStation\bios\ (Windows) · ~/.local/share/duckstation/bios/ (Linux) · ~/Library/Application Support/DuckStation/bios/ (macOS)

Fix 2: The file is still a ZIP

DuckStation reads the .bin file — not the archive. Extract the ZIP first. On Windows: right-click → Extract All. On macOS: double-click the ZIP.

Fix 3: File permissions (macOS/Linux)

On macOS or Linux, the BIOS file may not be readable by DuckStation. Run: chmod 644 scph1001.bin in the BIOS directory. Then restart DuckStation.

Fix: Re-download and verify file size

The file must be exactly 524,288 bytes. If not, it was corrupted during download or wasn't fully extracted. Re-download from a reliable source and check the size before placing it in the BIOS folder.

Fix 1: Region mismatch

You're running a Japanese or European game with a USA-only BIOS, or vice versa. The BIOS region-checks the disc during startup. Use the matching regional BIOS, or better — download the full pack and let DuckStation auto-select.

Fix 2: Fast boot skipping the boot sequence

Go to Settings → General → Enable Fast Boot and disable it. Some games require the full BIOS boot sequence to initialise correctly.

Fix 3: Corrupted disc image

The game file itself may be corrupted, not the BIOS. Try another copy of the disc image, or re-verify your CHD/BIN file with a checksum tool.

Fix 4: PGXP causing issues on this specific game

A small number of games conflict with PGXP Texture Correction. Right-click the game in your library → Game Properties → disable PGXP Texture Correction for that game only.

Fix: Place the BIOS in ePSXe's bios/ folder

ePSXe looks for BIOS files in a bios\ subfolder inside its own installation directory. Copy your .bin file there — for example C:\Program Files\ePSXe\bios\scph1001.bin. Then go to Config → Bios and select the file from the dropdown.

Fix: Filename must be lowercase

Some ePSXe versions are case-sensitive. Rename your BIOS to lowercase: scph1001.bin (not SCPH1001.bin).

Fix: Place BIOS in RetroArch's system/ folder

RetroArch's Beetle PSX HW core looks for BIOS files in the system folder, not a bios subfolder. Default location: Documents\RetroArch\system\ on Windows, ~/.config/retroarch/system/ on Linux.

Fix: Filename must match exactly

The filenames Beetle PSX HW expects are specific. The core requires: scph5500.bin (Japan), scph5501.bin (USA), scph5502.bin (Europe). If your file is named differently (e.g., SCPH-1001.BIN), rename it to match.

Fix: Use a v4.x BIOS

The DualShock vibration API was added in BIOS version 4.0. If you're using SCPH-1001 (v2.0) or SCPH-5501 (v3.0), vibration won't work in games that use it. Switch to SCPH-7001 (USA v4.1) for full vibration support. Then go to Settings → BIOS and confirm the v4.x version is selected.