emulator: melonDS
type: standalone + libretro
core_classification: community_fork
cores: [melonds]
source: "https://github.com/libretro/melonDS"
upstream: "https://github.com/melonDS-emu/melonDS"
profiled_date: "2026-03-24"
core_version: "Git"
display_name: "Nintendo - DS (melonDS)"
systems: [nintendo-ds, nintendo-dsi]

notes: |
  FreeBIOS fallback for DS mode (NTR); DSi mode requires all native files.
  Libretro fork based on melonDS ~0.9.x era, validates size only.
  Upstream adds CRC32 validation on BIOS files (MemConstants.h).
  DSi SD card emulation controlled by melonds_dsi_sdcard core option.

files:
  # --- Nintendo DS (NTR) ---
  - name: bios9.bin
    system: nintendo-ds
    description: "ARM9 BIOS"
    required: false
    hle_fallback: true
    size: 4096
    validation: {core: [size], upstream: [size, crc32]}
    crc32: "0x2ab23573"
    source_ref: "src/NDS.h:196, src/NDS.cpp:467-477, src/frontend/Util_ROM.cpp:99-111"
    note: "FreeBIOS fallback (src/FreeBIOS.h); native needed for Key1 cartridge crypto"

  - name: bios7.bin
    system: nintendo-ds
    description: "ARM7 BIOS"
    required: false
    hle_fallback: true
    size: 16384
    validation: {core: [size], upstream: [size, crc32]}
    crc32: "0x1280f0d5"
    source_ref: "src/NDS.h:197, src/NDS.cpp:482-492, src/frontend/Util_ROM.cpp:117-131"
    note: "FreeBIOS fallback (src/FreeBIOS.h); native needed for Key1 init at offset 0x0030"

  - name: firmware.bin
    system: nintendo-ds
    description: "NDS firmware image"
    required: false
    hle_fallback: true
    validation: [size]
    source_ref: "src/SPI.cpp:192-211, src/frontend/Util_ROM.cpp:174-195"
    note: "Generated 128KB firmware as fallback; native must be 256KB or 512KB for boot"

  # --- Nintendo DSi (TWL) ---
  - name: dsi_bios9.bin
    system: nintendo-dsi
    description: "DSi ARM9 BIOS"
    required: true
    size: 65536
    validation: {core: [size], upstream: [size, crc32]}
    crc32: "0xBAE84F6C"
    source_ref: "src/DSi.h:33, src/DSi.cpp:587-599, src/frontend/Util_ROM.cpp:145-156"

  - name: dsi_bios7.bin
    system: nintendo-dsi
    description: "DSi ARM7 BIOS"
    required: true
    size: 65536
    validation: {core: [size], upstream: [size, crc32]}
    crc32: "0x4316CC42"
    source_ref: "src/DSi.h:34, src/DSi.cpp:604-620, src/frontend/Util_ROM.cpp:158-170"
    note: "Contains eMMC key-Y at offset 0x8308 for NAND init"

  - name: dsi_firmware.bin
    system: nintendo-dsi
    description: "DSi firmware image"
    required: true
    size: 131072
    validation: [size]
    source_ref: "src/SPI.cpp:197-211, src/frontend/Util_ROM.cpp:201-217"

  - name: dsi_nand.bin
    system: nintendo-dsi
    description: "DSi NAND dump"
    required: true
    source_ref: "src/frontend/Util_ROM.cpp:224-235, src/DSi_NAND.cpp"
    note: "Uses AES keys from ARM7i BIOS offset 0x8308"

  - name: dsi_sd_card.bin
    system: nintendo-dsi
    description: "DSi SD card image"
    required: false
    source_ref: "src/frontend/Util_ROM.cpp:237-243, src/libretro/libretro.cpp:837,553"
    note: "Created if missing; requires melonds_dsi_sdcard core option enabled"