PS1 BIOS File: Which One You Need and Where to Put It
Which PS1 BIOS file matches your region, where DuckStation, RetroArch, and RetroApp look for it, and the errors that stop a game from booting.
A PS1 emulator will not boot a game without a BIOS. The BIOS is the firmware from a PlayStation console you own. It is not a shader, not a save, and not part of the game disc.
Which PS1 BIOS file to use
Pick the dump that matches the region of your console and your games:
- United States (NTSC-U): scph5501.bin. scph1001.bin is an older US dump that many cores still accept.
- Europe (PAL): scph5502.bin
- Japan (NTSC-J): scph5500.bin
A European game with a US BIOS can still run, but the boot logo, language, and timing follow the BIOS region. If the core offers a region override, set it to the game, not to whatever file happened to be first in the folder.
Dump the BIOS from a PlayStation you own. RetroApp, DuckStation, and RetroArch do not ship these files, and this guide will not link to downloads.
Where RetroArch looks
RetroArch reads BIOS files from the system directory. Check Settings, then Directory, then System/BIOS. Put scph5501.bin in that folder, not next to the game, and not inside a zip unless the core says it accepts one.
The Beetle PSX and SwanStation / DuckStation cores used by RetroArch expect the real filename. After you add the file, restart RetroArch so the core rescans the system directory.
Where DuckStation looks
DuckStation has its own BIOS list under Settings, then BIOS. Use the Add button and point it at the dump. DuckStation shows the region and a hash check. If the hash is unknown, the file was renamed, truncated, or is not a BIOS.
Keep one folder such as Documents/PS1/bios and add that folder once. Do not copy the BIOS into every game directory.
Where RetroApp looks
RetroApp scans a system folder so you do not have to open a core menu:
- Windows: AppData/Roaming/RetroApp/system/
- You can also drop the BIOS next to the ROM if you are only testing one game. The system folder is the one that survives library rescans.
Then scan the library again. A PS1 entry that stays on "missing BIOS" after a rescan is almost always a wrong filename or a dump that is still inside a zip.
Errors that look like a bad ROM
- Black screen, then exit. The BIOS is missing, or the core cannot read the filename.
- Wrong boot language. The BIOS region and the game region do not match. Swap to the matching SCPH file.
- Game boots in DuckStation but not in RetroArch. The files are in DuckStation's list and not in RetroArch's system directory. They are separate folders.
- "BIOS not found" after you moved the folder. Cores store an absolute path. Re-add the folder.
What to do after the BIOS works
In-game saves go to a virtual memory card. Save states are separate. Set both up with the save states and rewind guide so a boss fight does not depend on a memory card you forgot to create.
PS1 upscaling, texture filtering, and widescreen hacks live in the core options. They do not require a different BIOS. If the image is stretched, change the aspect ratio before you touch the BIOS again.
For the full launcher path, including covers and sessions with friends, use the PS1 emulator setup on Windows and the PS1 console page.
FAQ
Does every PS1 emulator need a BIOS?
Yes. PlayStation emulation expects a BIOS dumped from a console. SNES, NES, and Mega Drive do not. A PS1 game that immediately closes or sits on a black screen is often a missing or mismatched BIOS, not a bad disc image.
Which file should I use, scph5501 or scph1001?
scph5501.bin is the common US (NTSC-U) BIOS. scph5500.bin is Japan, scph5502.bin is Europe. scph1001.bin is an older US dump that also works in many cores. Match the BIOS region to the games you own.
Can I rename the BIOS file?
Only if the core documents that name. DuckStation and Beetle PSX look for known SCPH filenames. Dropping a file called bios.bin into a random folder usually does nothing.