emulator: RetroDream
type: libretro
core_classification: community_fork
source: "https://github.com/libretro/redream-next"
upstream: "https://github.com/inolen/redream"
profiled_date: "2026-03-25"
core_version: "Git"
display_name: "Sega - Dreamcast (RetroDream)"
cores:
  - retrodream
systems:
  - sega-dreamcast

notes: |
  Fork of the last GPLv3 release of redream (inolen) before it went closed-source.
  The core has HLE bootstrap -- when boot.bin is missing, bios_invalid_instr()
  traps at PC=0x0 and calls bios_boot(), which loads IP.BIN and 1ST_READ.BIN
  directly from disc, sets up syscall vectors, and starts execution at 0xac008300.

  The fork sets appdir to the RetroArch system directory root
  (retro_host.c:216-217), unlike the upstream which appends /dc
  (upstream retro_host.c:196-198). The .info still declares dc/ prefix paths
  matching the upstream, not this fork.

  boot.bin is validated against four known MD5 hashes (boot.c:25-30).
  Validation failure logs a warning but the core continues via HLE.

  flash.bin is read/write. If missing, bios_validate_flash() resets all
  partitions to defaults. Saved back to disk on shutdown (flash.c:197-199).

files:
  - name: "boot.bin"
    system: sega-dreamcast
    path: "boot.bin"
    required: false
    hle_fallback: true
    size: 2097152
    validation: [size, md5]
    md5:
      - a5c6a00818f97c5e3e91569ee22416dc
      - 37c921eb47532cae8fb70e5d987ce91c
      - f2cd29d09f3e29984bcea22ab2e006fe
      - e10c53c2f8b90bab96ead2d368858623
    note: "Dreamcast boot ROM. Four known variants accepted."
    source_ref: "src/guest/rom/boot.c:12-80"

  - name: "flash.bin"
    system: sega-dreamcast
    path: "flash.bin"
    required: false
    size: 131072
    validation: [size]
    note: "Dreamcast flash memory. Written back on shutdown."
    source_ref: "src/guest/rom/flash.c:25-71"