R36S BIOS Files: Complete Setup Guide

What Are BIOS Files and Why Does R36S Need Them?

BIOS stands for Basic Input/Output System — it is the original console's startup firmware, the low-level software that ran on the real hardware when you switched it on. Emulators replicate the console's hardware behavior in software, but some systems used their BIOS as an active part of the game boot process, handling disc authentication, memory card access, and audio initialization.

Emulators can simulate most of this behavior, but for certain systems the emulation is incomplete without the actual BIOS file from the original hardware. The emulator needs the real firmware to boot games correctly, handle copy protection checks, or produce accurate audio output.

Without the correct BIOS file in place, you will typically see one of several failure modes: games may not start at all, display a black screen, produce missing or distorted audio, or crash during the intro sequence before reaching gameplay.

Legal note: BIOS files are copyrighted by the original hardware manufacturers. You should dump them from console hardware you own rather than downloading them from the internet. Many communities discuss how to dump BIOS files from original hardware using a PC and appropriate software.

Which Systems Need BIOS Files?

Not every emulated system on the R36S requires a BIOS file. Many systems — including NES, SNES, Game Boy, and Mega Drive — work perfectly without one. The following table summarizes which systems need BIOS files and what happens without them.

Complete BIOS File List with Exact File Names

File names matter. BIOS files must be named exactly as the emulator expects, including correct capitalization. ArkOS and Rocknix run on Linux, where file names are case-sensitive — a file named SCPH1001.BIN will not be recognized if the emulator is looking for scph1001.bin.

PlayStation 1 BIOS Files

PS1 emulation requires at least one regional BIOS file. The USA BIOS (scph1001.bin) is the most widely compatible and the one most emulator cores default to. Regional BIOS files affect which games boot correctly — a PAL game may behave differently with a USA BIOS versus a European one.

Required files (at minimum one regional version):

• scph1001.bin — USA region, most common and recommended
• scph5500.bin — Japan region
• scph5501.bin — USA region v3
• scph7002.bin — Europe / PAL region

MD5 checksum for scph1001.bin: 924e392ed05558ffdb115408c263dccf

You can verify your BIOS file's integrity by checking its MD5 hash matches the value above. On Windows, open Command Prompt and run certutil -hashfile scph1001.bin MD5. On Linux, use md5sum scph1001.bin; on macOS the equivalent is md5 scph1001.bin, since macOS does not ship md5sum.

Dreamcast BIOS Files

Dreamcast is the system most often described as needing a BIOS, and it does not. The Flycast core ships a high-level reimplementation of the boot ROM and uses it automatically when no file is present, so games run without one. libretro's core definition marks dc/dc_boot.bin as optional and does not list dc_flash.bin at all — Flycast writes its own flash-memory file instead of reading one you provide. The requirement is inherited from Reicast, the older core Flycast replaced.

Optional, and worth adding anyway:

• dc_boot.bin — the real boot ROM. Adds the last slice of compatibility for the few titles that check for it, plus the genuine boot animation, the disc-less system menu and MIL-CD support.

If you add it, it goes in a /bios/dc/ subfolder rather than the /bios/ root where PS1's file lives. Getting that path wrong means the file is ignored and you fall back to the built-in BIOS — which is why the symptom is a few awkward games rather than nothing working.

Once the BIOS is in place, our Dreamcast emulation guide covers the Flycast settings that matter and which games are actually worth loading.

Sega CD / Mega CD BIOS Files

Sega CD emulation requires a regional BIOS file. Unlike Dreamcast, these go directly in the /bios/ folder with no subfolder needed. Use the file matching your game's region for best compatibility.

Our Genesis guide covers which core to use for Sega CD, and why region affects both the BIOS you need and the speed the game runs at.

• bios_CD_U.bin — USA region
• bios_CD_E.bin — Europe region
• bios_CD_J.bin — Japan region

Place these directly in the /bios/ folder on your SD card.

Game Boy Advance BIOS (Optional)

The GBA BIOS is technically optional — the lr-mgba and lr-gpsp cores can run most GBA games without it using a high-level emulation (HLE) BIOS built into the core. However, a small number of games rely on specific BIOS behavior that HLE does not replicate correctly, causing minor audio glitches or compatibility issues.

• gba_bios.bin
• MD5: a860e8c0b6d573d191e4ec7db1b1e4f6

The GBA BIOS is particularly important if you use the lr-gpsp core — that core specifically requires the real BIOS file to function correctly, unlike lr-mgba which handles HLE well.

Neo Geo BIOS

Neo Geo emulation requires a BIOS file that is distributed as a zip archive. Unlike most BIOS files, this one must remain zipped — do not extract it.

• neogeo.zip — must remain as a zip file, do not extract

Neo Geo is unusual in that the BIOS file must be placed in two locations: in your /bios/ folder AND in your roms/neogeo/ folder alongside your game ROMs. Some emulator configurations only check one location, so placing it in both ensures compatibility.

MAME / Arcade BIOS Files

Arcade emulation via MAME is more variable — individual arcade games may require their own system BIOS files, and requirements differ by game. The most commonly needed BIOS files for MAME are:

• neogeo.zip — for Neo Geo arcade games
• pgm.zip — for PolyGame Master board games
• awbios.zip, naomi.zip, naomi2.zip — for the Atomiswave and Naomi arcade boards, which run on Flycast rather than a MAME core

Place these BIOS zip files in the same folder as your arcade ROMs, or in /bios/. Check the error output when a game fails to launch — MAME typically reports which BIOS file it is looking for.

There is no CPS-1 or CPS-2 BIOS zip to find, despite frequent claims otherwise. Capcom board games carry what they need inside their own romset, so if a CPS-2 game will not start the problem is the romset version rather than a missing BIOS.

Arcade has one more requirement that no console system has: the romset itself must match the version of the core loading it. Our arcade and MAME guide explains that relationship and how to read the resulting errors.

Where to Put BIOS Files (Exact Paths)

The correct folder path depends on which firmware your R36S is running. ArkOS and Rocknix use different folder structures, but the BIOS folder names are consistent within each firmware. To access the SD card, plug it into your PC — the ROMS partition will appear as a drive in File Explorer (Windows) or Finder (Mac).

If you are not sure which firmware your R36S is running, check the main menu or settings screen. ArkOS shows "ArkOS" in the corner; Rocknix shows its own branding. The stock firmware that ships with many R36S units uses a different folder structure again — check your specific firmware's documentation if neither path above works.

How to Verify BIOS Files Are Working

After placing your BIOS files, you should verify they are being detected correctly before assuming everything is set up. There are two methods: using RetroArch's built-in BIOS checker, or simply testing by launching a game.

Method 1 — RetroArch BIOS Check

RetroArch includes a built-in tool that scans for BIOS files and reports which ones it can find:

1. Open RetroArch directly (not through EmulationStation)
2. Navigate to Settings → System → BIOS
3. Alternatively: Main Menu → Load Core → select a PS1 core → check BIOS status
4. RetroArch displays a green checkmark next to BIOS files it has detected, and a red X next to missing ones

A green checkmark confirms RetroArch can see the file, the name is correct, and it is in the right location. A red X means the file is missing, misnamed, or in the wrong folder.

Method 2 — Test Launch a Game

The most practical test is simply launching a PS1 game after placing your BIOS files:

• If the game boots and you see the PlayStation startup screen (grey Sony logo with startup chime) → the BIOS is working correctly
• If you see a black screen immediately → the BIOS is missing or not being found
• If the game crashes during the intro before reaching gameplay → the BIOS may be the wrong version or a corrupted file

Common Errors and Causes

"BIOS not found" error message: The file name is wrong (check capitalization) or the file is in the wrong folder. Double-check the exact file name and confirm the folder path matches your firmware.

Game boots but audio is missing or incorrect: You may have the wrong region BIOS. A Japanese game may have audio issues with a USA BIOS file. Try adding the matching regional BIOS.

Dreamcast games all show black screen: This is not a BIOS problem — Flycast boots without one. Check the game image and the core, using our boot and display troubleshooting guide.

Troubleshooting BIOS Issues

PS1 Games Still Won't Boot After Adding BIOS

If PS1 games are still not booting after you have added a BIOS file, work through these checks in order:

1. Confirm the file name is exactly scph1001.bin in lowercase. Even a single capital letter will cause it to not be found on Linux-based firmware.
2. Confirm the file is in /roms/bios/ and not accidentally placed in /roms/ or in a folder called just /bios/ at the root of the card.
3. Try a different emulator core. PCSX ReARMed and DuckStation handle BIOS files differently and look for them in slightly different ways. If one core fails, try the other.
4. Confirm your ROM is a valid format. PS1 games should be in .cue + .bin pair format, .chd, or .pbp. A .bin file without a matching .cue file will not launch correctly in most cores.
5. Check the BIOS file is not corrupted by verifying its MD5 checksum against the known-good value listed above.

Dreamcast Black Screen

Black screens on Dreamcast are commonly blamed on the BIOS, and that diagnosis is wrong: Flycast runs without one. Work through these instead:

• Confirm the game image itself is sound — a truncated or bad CHD/GDI dump is the more likely cause
• Confirm Flycast is the core actually being used, rather than an older Reicast build
• If you did supply dc_boot.bin, confirm it is in /roms/bios/dc/; a misplaced or corrupt file is ignored rather than fatal, but a corrupt one in the right place is not
• Our boot and display troubleshooting guide covers black screens that are not game-specific at all