Where to Put BIOS Files in RetroArch (PS1 and PS2 BIOS Guide)

AvatarByEric Dawson Computers & Software

RetroArch reads BIOS files from a single folder called the system directory, and that is where you put them. On Windows the default is C:/Users/YOUR_USERNAME/AppData/Roaming/RetroArch/system, on macOS it is /Users/YOUR_USERNAME/Library/Application Support/RetroArch/system, and on Linux it is ~/.config/retroarch/system. Confirm the live path under Settings > Directory > System/BIOS. Most cores, including the PlayStation 1 ones, want the files loose in that folder with no subfolders. PlayStation 2 is the exception, and its core looks in system/pcsx2/bios instead. Names have to match exactly, and RetroArch needs a restart before it notices anything new.

Where RetroArch Looks for BIOS Files

Every core that needs firmware checks one place: the system directory. RetroArch does not scan your drive for stray .bin files, and it will not look inside folders you created to keep things tidy. If a core wants scph5501.bin, it wants that file sitting directly in the system folder under that exact name. Libretro’s own BIOS documentation describes the layout the same way, which is why the same advice keeps getting repeated on forums.

One folder, no nesting, covers the PlayStation 1 cores and nearly everything else. PlayStation 2 breaks the pattern, and that catches out people who set up PS1 emulation first and assume the rest works the same. Details on that are further down.

The Default System Folder on Windows, macOS and Linux

Fresh installs use the paths below, according to the Lutris project documentation and the RetroArch BIOS setup guide hosted on GitLab, both read in September 2026.

  • Windows: C:/Users/YOUR_USERNAME/AppData/Roaming/RetroArch/system
  • macOS: /Users/YOUR_USERNAME/Library/Application Support/RetroArch/system
  • Linux: ~/.config/retroarch/system

Android is the odd one out, because the install method changes the path and no single default holds. Portable builds and some store versions on desktop behave the same way, keeping the system folder next to the executable rather than in your user profile. Whatever the menu reports is the truth; a guide written for a different install is not.

How to Check and Change the Folder in RetroArch

Open the main menu, go to Settings, then Directory. Scroll down to the entry labeled System/BIOS. The path shown there is the folder your cores actually read.

Changing it means selecting that entry, browsing to the folder you want, and confirming the selection. Any directory your user account can read will do, as regulars on the Libretro forums point out when people ask about keeping firmware on a second drive. Moving the folder does not move the files, so copy them across yourself afterwards.

How to Add BIOS Files Step by Step

Add BIOS files by copying them directly into the system directory using their exact filenames, then restart RetroArch so the cores can find them.

  1. Find the folder: in RetroArch, open Settings > Directory > System/BIOS and note the path.
  2. Open that path in your file manager: on Windows you can paste %APPDATA%/RetroArch/system into the address bar of File Explorer.
  3. Copy the files in loose: no subfolder, no archive, no folder named bios inside the system folder.
  4. Match the names exactly: scph5501.bin is not scph5501.BIN on a case sensitive file system, and it is not scph5501.bin.bin.
  5. Restart RetroArch: close it fully rather than backing out of the menu.
  6. Load a game and watch the notifications: cores announce missing firmware on screen as they start.

Restarting matters more than people expect. The GitLab setup guide calls it out specifically, because cores check for firmware at load time and nothing rescans the folder while RetroArch is running.

Which PS1 BIOS to Use

Three regional files cover the PlayStation 1: scph5500.bin for Japan, scph5501.bin for North America, and scph5502.bin for Europe. Beetle PSX, Beetle PSX HW and PCSX ReARMed all expect firmware, and the file should match the region of the disc image you are loading. Most people copy all three in once and stop thinking about it.

Region Filenames and MD5 Checksums

Checksums separate a good dump from a corrupt or simply renamed one. Every desktop operating system ships with a tool that computes them.

  • Windows: certutil -hashfile scph5501.bin MD5
  • macOS: md5 scph5501.bin
  • Linux: md5sum scph5501.bin

Compare the output against the values in the reference table below. A mismatch means the file is not what its name claims, and no amount of moving it between folders will change that. Renaming a European dump to scph5501.bin fools the core into loading it and then produces odd timing or boot behavior, which is the usual cause of a game that runs but feels wrong.

Where SCPH1001.bin Fits In

Older setup guides name the North American firmware SCPH1001.bin instead, and the PS1 BIOS config site still recommends that revision as the most broadly compatible one. Both naming schemes refer to real retail firmware, so the disagreement is about which dump a given guide expects rather than which one is legitimate. Current Libretro documentation and the Lutris notes use the scph5500, scph5501 and scph5502 set, so start there. Keep SCPH1001.bin in mind only if a core reports missing firmware while naming that file.

My practical call is to use the scph5500.bin, scph5501.bin, and scph5502.bin set rather than treating SCPH1001.bin as the default answer. The three-file set gives each game its matching Japan, North America, or Europe firmware, which is the cleaner choice when region matching affects compatibility. SCPH1001.bin may be useful when a core specifically asks for it, but I would regard it as a fallback rather than the starting point. Copying all three regional files once avoids having to guess which single BIOS will suit every game.

Which PS2 BIOS to Use in RetroArch

PlayStation 2 needs a dumped BIOS file matching your console’s region, loaded into RetroArch’s LRPS2 core: ps2-0230a-20080220.bin for North America, ps2-0230e-20080220.bin for Europe, or ps2-0230j-20080220.bin for Japan. Firmware is mandatory here. No high-level emulation fallback exists, so without a dumped BIOS the core will not boot a disc image at all.

The LRPS2 Core and Its Own BIOS Folder

Here is the exception to the no-subfolders rule. LRPS2 reads firmware from system/pcsx2/bios, a path you will probably have to create by hand, and it stores virtual memory cards in system/pcsx2/memcards. Game compatibility settings live at system/pcsx2/resources/GameIndex.yaml, although current builds embed that database and only read the folder copy when you deliberately override it.

Hardware requirements are steep compared with the PS1 cores. Libretro lists 64-bit Windows, macOS and Linux on x86_64 as the supported platforms, with a graphics chip capable of Direct3D 10 or 11, OpenGL 3.x, or Vulkan 1.3, between 2GB and 4GB of video memory, and 4GB to 8GB of system memory. ARM devices are out entirely, so Android handhelds, iOS and Windows on ARM cannot run it, and Apple silicon Macs manage only through Rosetta. Rewind and netplay are unsupported, and the LRPS2 documentation warns that some games will not reach full speed even on recommended hardware.

PS2 BIOS Filenames and the Extra Files

Dumps circulate under names such as ps2-0230a-20080220.bin for North America, ps2-0230e-20080220.bin for Europe and ps2-0230j-20080220.bin for Japan, each tied to the console revision it came from. Names in the SCPH-39001.bin style show up for US consoles as well. Unlike the PS1 cores, LRPS2 does not demand one specific filename: it wants a 4MB .bin file, and any companion files your dumper produced have to share the same base name.

Those companions are the erom, nvm, rom1 and rom2 files, written as filename.erom, filename.nvm and so on. The .nvm file holds settings specific to the console it was pulled from, including its region and clock. Keep the whole set together in system/pcsx2/bios rather than picking out the main .bin.

BIOS Filename and Checksum Reference Table

The table below lists the exact filename and MD5 hash for each PS1 BIOS region, along with the PS2 filenames, which have no listed hash because those dumps vary from console to console. Figures come from the RetroHandheldHQ firmware roundup and the Lutris project’s RetroArch notes, both read in September 2026.

Console Region Filename MD5 hash Goes in
PS1 Japan scph5500.bin 8dd7d5296a650fac7319bce665a6a53c system
PS1 North America scph5501.bin 490f666e1afb15b7362b406ed1cea246 system
PS1 Europe scph5502.bin 32736f17079d0b2b7024407c39bd3050 system
PS1 North America, older naming SCPH1001.bin Not published by the sources read system
PS2 North America ps2-0230a-20080220.bin Varies by dump system/pcsx2/bios
PS2 Europe ps2-0230e-20080220.bin Varies by dump system/pcsx2/bios
PS2 Japan ps2-0230j-20080220.bin Varies by dump system/pcsx2/bios

How to Dump a BIOS from a PS2 You Own

Dumping a PS2 BIOS means pulling the firmware off a console you already own, using a memory card running FreeMcBoot and the uLaunchELF file manager to write it to a USB drive. Downloading firmware instead breaks copyright law, since Sony owns the code and no site distributing those files holds a license, so a personal dump is the only legitimate route.

What You Need Before You Start

Four things, and one of them takes far longer to arrange than the rest.

  • A PlayStation 2 you own: the dump has to come off your own hardware.
  • A memory card running FreeMcBoot: this softmod is what lets the console launch homebrew from the card.
  • A USB flash drive formatted to FAT32: the dump gets written here, and FAT32 is the format the console expects.
  • uLaunchELF: the homebrew file manager that performs the dump.

Installing FreeMcBoot is a separate project, and none of the sources read for this article document that process. Sort it out first, since every step below assumes the card already boots into the FreeMcBoot menu.

Dumping the BIOS Step by Step

  1. Boot with the card inserted: put the FreeMcBoot memory card in and power on the PS2. FreeMcBoot replaces the usual browser screen.
  2. Launch uLaunchELF: select it from the FreeMcBoot menu.
  3. Plug in the USB drive: it shows up in the file browser as mass:/.
  4. Open the MISC menu: choose the BIOS dump option from it.
  5. Pick mass:/ as the destination: writing to the memory card instead risks running out of space.
  6. Wait for it to finish: under a minute is normal.
  7. Move the files to your PC: then copy them into system/pcsx2/bios.

Output is a 4MB .bin file, and many consoles also produce the rom1, rom2, erom and nvm companions described earlier. Copy all of them across together.

Verifying the Dump Against Known Hashes

Run the same MD5 command you would use on a PS1 file, then check the result against the PCSX2 wiki list of known-good hashes for official BIOS revisions. A matching value means the dump is clean and the core will accept it. Anything else usually points at a flaky USB drive or a write that got interrupted, and dumping again is quicker than diagnosing it.

If RetroArch Still Says the BIOS Is Missing

A missing-BIOS message almost always traces back to the exact system path, a nested subfolder, a hidden file extension, mismatched filename case, a skipped restart, or an unverified checksum. Check each of these before assuming the dump itself is bad.

  • Read the path from the menu, not from a guide: Settings > Directory > System/BIOS beats any default you found online.
  • Look for a nested folder: extracting an archive into the system directory often creates system/bios/scph5501.bin, one level too deep.
  • Check the extension: Windows hides known file types by default, so a file displayed as scph5501.bin may really be scph5501.bin.bin.
  • Match the case: Linux and Android file systems treat scph5501.bin and SCPH5501.BIN as different files.
  • Restart after copying: firmware detection happens when a core loads, not while you are browsing menus.
  • Verify the MD5: a renamed or truncated file passes the name check and fails everything after it.
  • For PS2, use the subfolder: system/pcsx2/bios, created manually if RetroArch has not made it.

One more trap is worth knowing about. Adding firmware after you have already been playing can invalidate your existing save states, since forum regulars describe states as extremely volatile snapshots of emulator memory and the BIOS changes what sits in that memory. Finish anything you care about with an in-game save to a virtual memory card before you start swapping files around.

Frequently Asked Questions

Can I Keep All Three PS1 BIOS Files in the Folder at Once?

Yes. Cores load firmware by exact filename, so scph5500.bin, scph5501.bin and scph5502.bin coexist without conflict, and the RetroHandheldHQ guide describes collecting all three as normal practice for playing games from different regions. None of the sources read for this article document a downside to having extras present.

Does RetroArch Download BIOS Files for Me?

No. RetroArch downloads cores, thumbnails and assets through its own updater, but firmware is not included, because Sony still holds the copyright on it. Anyone distributing those files online is infringing that copyright, which is why the legitimate route is dumping from hardware you own.

Do PS1 and PS2 Games Run Without Any BIOS at All?

PS2 needs firmware without exception, since LRPS2 has no high-level emulation substitute for it. For PlayStation 1, Libretro lists firmware as a requirement for Beetle PSX, Beetle PSX HW and PCSX ReARMed, and even where a core tolerates its absence, real firmware gives better compatibility. Treat it as mandatory for both systems.

Where Do BIOS Files Go on Android?

There is no fixed answer, because the path depends on how RetroArch was installed on that device. Open Settings > Directory > System/BIOS on the device itself and use whatever it reports. Keep in mind that PS2 emulation through LRPS2 does not run on ARM hardware, so Android covers PS1 but not PS2.

Why Did My Save States Break After I Added a BIOS?

Save states capture the emulator’s exact memory contents at a moment in time, so anything that changes how the core boots can make an old state unreadable. Adding or swapping firmware does exactly that. Libretro forum users call states extremely volatile for this reason and recommend in-game saves for anything you want to keep long term.

Get the folder right first, verify the checksums second, and most RetroArch firmware problems disappear. Settings > Directory > System/BIOS tells you the one path that matters, PS1 files sit loose in it, and LRPS2 wants its own system/pcsx2/bios subfolder underneath. Dump from your own console, keep the companion files with the main .bin, and restart the program before you decide something is broken.

What This Page Does Not Publish

  • I do not list every PS2 BIOS checksum here; valid dumps vary by console revision.
  • I do not cover FreeMcBoot memory card setup; it is separate from placing BIOS files in RetroArch.
  • I do not prescribe a preferred mix of multiple PS2 BIOS versions in one folder.

References

Author Profile

Eric Dawson
Eric Dawson
I'm Eric Dawson, the writer behind The Money Watch. I live in the Columbus, Ohio area and I write about the ordinary questions that turn out to be complicated: computers, shopping, food, travel, parking, small businesses, fees, rules and products. Every article starts with the official page, the maker or the agency, then the sources that check it, and I say plainly where they disagree and what I would do. More about how I work is on the About page.