emulator: no$gba
type: standalone
core_classification: embedded_hle
source: "https://problemkaputt.de/gba.htm"
upstream: "https://problemkaputt.de/gba.htm"
version_source:
  url: "https://problemkaputt.de/gba.htm"
  pattern: 'no\$gba v(\d+(?:\.\d+)+)'
profiled_date: "2026-10-20"
core_version: "3.04"
display_name: "Nintendo - GBA/DS/DSi (no$gba)"
cores:
  - nosgba
systems:
  - nintendo-gba
  - nintendo-ds
  - nintendo-dsi
  - sony-pocketstation
mode: standalone

notes: |
  Freeware gaming build of Martin Korth's Game Boy Advance, Nintendo DS and
  DSi emulator for Windows, closed source. RetroBat installs it as nosgba and
  starts NO$GBA.EXE with the ROM. Its NO$GBA.EXE (220079 bytes, sha1
  935b857bc1249479124247612755eeb2a247f23c) is the one in no$gba-w.zip of
  v3.04, 23 Mar 2021, byte for byte. The official zip also carries
  DSI-SD.ZIP, which RetroBat leaves out. Everything below is read from that
  executable after removing its UPX layer. Addresses are virtual addresses of
  the unpacked image (base 0x400000).

  Every file is opened by bare name. Before each open the program builds its
  own folder from the module path and makes it the current directory
  (0x431741, 0x4316ea), so all of them sit next to NO$GBA.EXE.

  The boot ROMs come from one table of six slots (0x471a81-0x471b80), loaded
  by one routine (0x4357c6-0x4358a1). For each slot it clears the buffer, then
  tries a list of (file, offset) pairs in order. The first file that opens and
  is longer than its offset gives the bytes, read at that offset for the slot
  size. No size is checked beyond that. The lists:
  GBA, 16 KiB: NO$GBA.ROM at 0, BIOSGBA.ROM at 0, GBA.ROM at 0.
  NDS ARM7, 16 KiB: NO$GBA.ROM at 0x4000, BIOSNDS.ROM at 0, BIOSNDS7.ROM at 0.
  NDS ARM9, 4 KiB: NO$GBA.ROM at 0x8000, BIOSNDS.ROM at 0x4000, BIOSNDS9.ROM at 0.
  DSi ARM7, 64 KiB: BIOSDSI.ROM at 0, BIOSDSI7.ROM at 0.
  DSi ARM9, 64 KiB: BIOSDSI.ROM at 0x10000, BIOSDSI9.ROM at 0.
  PocketStation, 16 KiB: POCKSTAT.ROM at 0.
  NO$GBA.ROM, BIOSNDS.ROM and BIOSDSI.ROM are therefore concatenations of the
  single images, GBA then ARM7 then ARM9.

  After a slot loads, two 32-bit words are computed over it: the sum of its
  dwords, and a value seeded with 0x42494f53 that takes each dword plus the
  count of dwords left, XORs it in and rotates right by one. The GBA, NDS ARM7,
  NDS ARM9 and PocketStation slots carry the expected pair, the DSi slots carry
  none. A mismatch only raises "Incorrect GBA/NDS BIOS version!" and the image
  stays in use (0x43586a-0x43589a, 0x4358f0-0x43591e). The md5 and sha1 given
  below are those of the dumps that produce the expected pair.

  Without a GBA image the slot receives a 236-byte stub held in the executable
  (0x43578c-0x4357c5) and the BIOS calls run as x86 code, the default of the
  "Emulate BIOS Functions" option. Only the BIOS sound functions then stop with
  "Sorry, no$gba needs a copy of the original GBA BIOS". The NDS slots stay
  zero and the calls are emulated the same way. The ARM7 image is what
  decrypts the secure area of an encrypted cartridge dump and CodeBreaker
  codes ("Encrypted Cartridge, requires files BiosNds7.rom and BiosNds9.rom").
  Without a PocketStation image a built-in clone named pockclon is expanded in
  its place (0x435750-0x435771). DSi mode needs the DSi images for their RSA
  keys and stops with "Missing DSi BIOS dump (need RSA keys)" without them.

  The DSi eMMC and SD card are files named from the emulated unit number, 1 for
  the first machine: the name is written over a template as "DSi-", the digit,
  then "mmc" or "sd" (0x43acea-0x43ad2d). The eMMC image must carry the
  nocash footer with the CID and console ID ("Missing footer in .mmc file").
  The template string itself reads New3DS-#.mmc, from the 3DS mode.

  Written rather than obtained: NO$GBA.INI (generated config), NO$GBA.INP (key
  setup), saves under BATTERY, snapshots under SLOT, QUIKSAVE.SNA, and
  FIRMnnnn.BIN and BIOS dumps the xboo cable tools write. NO$GBA.CHT is a
  cheat list the user writes, help.htm and help.txt are documentation, and
  no$gba.key is the registration file of the debug version.

files:
  - name: BIOSGBA.ROM
    aliases: ["GBA.ROM"]
    system: nintendo-gba
    required: false
    hle_fallback: true
    size: 16384
    md5: "a860e8c0b6d573d191e4ec7db1b1e4f6"
    sha1: "300c20df6731a33952ded8c436f7f186d25d3492"
    on_mismatch: warn
    description: "Game Boy Advance BIOS"
    note: >
      Tried after NO$GBA.ROM and before GBA.ROM. Expected checksum pair
      0xbaae187f, 0xc98cfa1d, which the retail GBA BIOS gives. Needed for the
      BIOS sound functions and the Nintendo logo boot.
    source_ref: "NO$GBA.EXE v3.04 0x471a81-0x471aac (slot), 0x4357c6-0x43589a (load and checksum), 0x43578c-0x4357c5 (stub when absent)"

  - name: BIOSNDS7.ROM
    system: nintendo-ds
    required: false
    hle_fallback: true
    size: 16384
    md5: "df692a80a5b1bc90728bc3dfc76cd948"
    sha1: "24f67bdea115a2c847c8813a262502ee1607b7df"
    on_mismatch: warn
    description: "Nintendo DS ARM7 BIOS"
    note: >
      Tried after NO$GBA.ROM at 0x4000 and BIOSNDS.ROM at 0. Expected checksum
      pair 0xbc180972, 0x36b3e1b2. Carries the key that decrypts encrypted
      cartridge secure areas and CodeBreaker codes.
    source_ref: "NO$GBA.EXE v3.04 0x471ab1-0x471adc (slot), 0x4357c6-0x43589a (load and checksum)"

  - name: BIOSNDS9.ROM
    system: nintendo-ds
    required: false
    hle_fallback: true
    size: 4096
    md5: "a392174eb3e572fed6447e956bde4b25"
    sha1: "bfaac75f101c135e32e2aaf541de6b1be4c8c62d"
    on_mismatch: warn
    description: "Nintendo DS ARM9 BIOS"
    note: >
      Tried after NO$GBA.ROM at 0x8000 and BIOSNDS.ROM at 0x4000. Expected
      checksum pair 0xbb212bf7, 0x1bec1d77.
    source_ref: "NO$GBA.EXE v3.04 0x471ae1-0x471b0c (slot), 0x4357c6-0x43589a (load and checksum)"

  - name: FIRMWARE.BIN
    system: nintendo-ds
    required: false
    hle_fallback: true
    max_size: 524288
    description: "Nintendo DS firmware flash"
    note: >
      Read whole into a buffer of 256 KiB, or 512 KiB when the file is larger.
      A file over 512 KiB stops the program with "Unexpected Error". Absent, a
      256 KiB buffer stands in. No hash is checked.
    source_ref: "NO$GBA.EXE v3.04 0x4356a8-0x4356e8 (load), 0x4358a2-0x4358d3 (buffer size), 0x4348fa (error)"

  - name: BIOSDSI7.ROM
    system: nintendo-dsi
    required: false
    size: 65536
    description: "Nintendo DSi ARM7 BIOS"
    note: >
      Tried after BIOSDSI.ROM at 0. No checksum. DSi mode stops without it
      since it holds the RSA keys.
    source_ref: "NO$GBA.EXE v3.04 0x471b11-0x471b38 (slot), 0x4357c6-0x435802 (load)"

  - name: BIOSDSI9.ROM
    system: nintendo-dsi
    required: false
    size: 65536
    description: "Nintendo DSi ARM9 BIOS"
    note: "Tried after BIOSDSI.ROM at 0x10000. No checksum."
    source_ref: "NO$GBA.EXE v3.04 0x471b39-0x471b60 (slot), 0x4357c6-0x435802 (load)"

  - name: WIFI-DSI.BIN
    system: nintendo-dsi
    required: false
    hle_fallback: true
    description: "DSi wifi firmware flash"
    note: >
      Read whole. Absent, a 128 KiB buffer stands in. No hash is checked.
    source_ref: "NO$GBA.EXE v3.04 0x435701-0x435741 (load), 0x4358d4-0x4358ef (buffer)"

  - name: AR6002G.ROM
    system: nintendo-dsi
    required: false
    description: "Atheros AR6002 wifi chip ROM"
    note: >
      Read for a DSi when the byte at firmware offset 0x1fd is not 2. Absent,
      the ROM area is filled with 0x55.
    source_ref: "NO$GBA.EXE v3.04 0x46014c-0x4601bd"

  - name: AR6013G.ROM
    system: nintendo-dsi
    required: false
    description: "Atheros AR6013 wifi chip ROM"
    note: "Read for a DSi when the byte at firmware offset 0x1fd is 2. Absent, the ROM area is filled with 0x55."
    source_ref: "NO$GBA.EXE v3.04 0x46014c-0x4601bd"

  - name: DSi-1.mmc
    system: nintendo-dsi
    required: false
    description: "DSi eMMC image with nocash footer"
    note: >
      eMMC of the first emulated DSi. The footer has to carry the CID and the
      console ID. No hash or size is checked.
    source_ref: "NO$GBA.EXE v3.04 0x43acea-0x43ad65"

  - name: DSi-1.sd
    system: nintendo-dsi
    required: false
    size: 125698048
    md5: "a5feb3d3fc0cdf0f663ef1a80ba39e72"
    sha1: "b473e101c7d22c15272f3cfce7c30b01f67839b4"
    description: "DSi SD card image"
    note: >
      SD card of the first emulated DSi. The official zip ships a blank
      FAT16 one as DSI-1.SD inside DSI-SD.ZIP. The hashes are those of that
      file, the code checks none.
    source_ref: "NO$GBA.EXE v3.04 0x43acea-0x43ad65"

  - name: POCKSTAT.ROM
    system: sony-pocketstation
    required: false
    hle_fallback: true
    size: 16384
    md5: "3bcdcef3d9aa7af85cd45e29986d11c8"
    sha1: "6ae880493ddde880827d1e9f08e9cb2c38f9f2ec"
    on_mismatch: warn
    description: "PocketStation BIOS"
    note: >
      Expected checksum pair 0x27e94c07, 0x63beca34, given by the image ending
      in J061. An image ending in J110 is checked against 0xb16ce96c,
      0xbedf0d0f instead, and one with POCKBIOS at 0x40 is not checked.
      Absent, a built-in clone is used.
    source_ref: "NO$GBA.EXE v3.04 0x471b61-0x471b80 (slot), 0x43582b-0x435863 (variant tests), 0x435750-0x435771 (clone)"