Solution: RetroArch is looking in the wrong directory. Create system/dc/ inside your RetroArch root folder, not the core's folder.
Developers using KallistiOS (KOS) need to understand the BIOS calls. While modern homebrew bypasses the BIOS for hardware access, low-level initializations still depend on the boot ROM to set up the memory map.
The Sega Dreamcast remains one of the most beloved consoles from the late 1990s. For retro collectors, emulation hobbyists, and preservationists, two files often come up when working with Dreamcast hardware or emulators: dc-boot.bin and dc-flash.bin. This post explains what these files are, how they’re used, and important legal and practical considerations when handling them.
Demul requires a specific hashed version of the BIOS files.
Even with the correct files, things can go wrong. Here is the troubleshooting flowchart.