To get Dreamcast emulation working on EmuDeck, you need to ensure the BIOS files are correctly named and placed in the right directory. While EmuDeck's Flycast emulator uses a high-level emulation (HLE) BIOS by default that allows some games to run without external files, a physical BIOS dump is highly recommended for full compatibility and to avoid common launch issues EmuDeck Wiki 1. Required BIOS Files
If you frequently reset EmuDeck or re-image your Steam Deck, manually copying BIOS is tedious. Use this power-user tip:
Without the BIOS, an emulator cannot:
Modern Dreamcast ROMs use .chd (compressed hunks of data). Older guides suggest .gdi. If you are using .gdi files, you must keep them in a folder with the .raw track files. Flycast gets confused if the folder structure is messy.
Conclusion
Why is my Dreamcast BIOS missing?
If you are trying to play arcade games that ran on Dreamcast hardware (like Metal Slug 6 or Dolphin Blue), you actually need the NAOMI BIOS. Same folder, different files: dreamcast bios missing emudeck work
Cause: Flycast requires the BIOS to be unzipped and unencrypted. Some dumps are in .zip or encrypted for other emulators. Use a raw binary dump.