you are using (e.g., RetroArch, Mega EverDrive Pro, OpenEmu)
: Ensure your Windows settings have "File name extensions" checked. A common error is naming a file mcd-us.bin.bin because the .bin part was hidden during renaming. Common Issues & Troubleshooting File Not Found Error
Use (Microsoft Sysinternals) or OpenFiles command:
and systems like the MiSTer, your BIOS file must match specific parameters: Exactly 131,072 bytes (128 KB) . mcd-us.bin
This exact file naming convention is widely recognized across multiple major retro gaming platforms: Platform Type Target Device / Software Directory Path Krikzz Mega EverDrive Pro SD://MEGA/bios/ FPGA Console Analogue Mega Sg SD://BIOS/ Software Emulator RetroArch (Genesis Plus GX / Picodrive) RetroArch/system/ Software Emulator Kega Fusion Custom defined in Set Configuration Step-by-Step Installation Guide
is the essential BIOS file required to emulate or play Sega CD (Mega CD) games from the North American region on modern hardware.
Because Sega CD hardware was region-locked, you typically need three distinct BIOS files to play games from all over the world: : For North American (USA) games. mcd-jp.bin : For Japanese games. mcd-eu.bin : For European (PAL) games. How to Use mcd-us.bin If you are setting up a Mega EverDrive Pro Go to product viewer dialog for this item. you are using (e
Depending on your setup, the file must be placed in a specific folder so the software can find it.
If you are setting up a hardware flash cart, follow this directory layout on your microSD card: Open the root directory of your formatted microSD card. Locate or create a folder named MEGA . Inside the MEGA folder, create a subfolder named bios . Paste your file directly into that folder.
mcd-us.bin is not a legitimate update or driver. It is an active threat targeting unsecured Linux devices. Ensure your firmware is updated and default passwords are changed immediately. This exact file naming convention is widely recognized
You can usually specify the location of the BIOS file in Options > Set Config > Sega CD . 2. Correct Naming Convention
To configure the mcd-us.bin file for hardware playback or emulation, you must place it in the correct directory and format it exactly as specified by the system developers. Directory Mapping for Mega EverDrive Pro
Are you trying to get this working on a (like EverDrive)? Are you setting up an emulator on your PC or Steam Deck?
Most modern setups are case-sensitive. Ensure your file is named exactly mcd-us.bin (all lowercase). Depending on your device, you might also see it referred to as: us_scd_v1_92.bin (the version often found in dumps) bios_CD_U.bin Where does it go?