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RetroBIOS

Hatari

Hatari emulates Atari ST, Atari STE, Atari TT and Atari Falcon. It reads 9 files, 1 of them required: without a required file it does not start games. A required file is needed only by the machines that use it. Each file below cites the line of source code that reads it.

Run on its own, the app reads its files from this folder:

%USERPROFILE%/AppData/Local/Hatari/

Holds hatari.cfg, hatari.nvram and auto.sav. The default tos.img is read from the directory of the executable.

Source: src/paths.c:24-29 (upstream emulator), src/paths.c:201-274 (upstream emulator)
About this profile
Detail Value
Type standalone + libretro
Classification Official port
Source https://github.com/libretro/hatari
Upstream https://github.com/hatari/hatari
Version 2.6.1-devel, stated in src/includes/version.h
Revision libretro/hatari@50929946d196, hatari/hatari@23bc3060ebf0
Profiled 2026-10-21
Profile YAML, JSON
Cores hatari, HATARISA
Systems Atari ST, Atari STE, Atari TT, Atari Falcon
Data folder (Windows) %USERPROFILE%/AppData/Local/Hatari/
Data folder (macOS) ~/Library/Application Support/Hatari/
Data folder (Linux) ~/.config/hatari/
Install this emulator's files

For Hatari inside RetroArch, Batocera or another setup. The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell
&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator hatari
Technical notes

The main branch of libretro/hatari is the upstream Hatari tree with its experimental libretro target in src/retro, which upstream added in January 2026, plus the port commits that follow their merge base, 51ed9991: VFS, disk control, core options, hard disk loading, the virtual keyboard, drive LEDs and the floppy drive sound. It builds as hatari_libretro (.gitlab-ci-libretro.yml:10-11, src/CMakeLists.txt:371-404), reports library_name hatari and the HATARI_VERSION string 2.6.1-devel (src/retro/main_retro.c:223-224, src/includes/version.h:8). The .info shipped in the tree declares no firmware (share/libretro/info/libretro-hatari.info). The hatari_libretro.info in libretro-core-info took that file's metadata on 2026-09-16 and keeps a tos.img firmware entry with the TOS 1.02 US MD5, which this code never checks.

retro_init builds <system>/tos.img, records whether it exists and passes it as --tos (src/retro/main_retro.c:160-211). It first reads floppy.raw from the system directory as the floppy drive sample (src/retro/main_retro.c:185, src/retro/floppy_sound.c:146-186). When tos.img is absent a frontend message is shown and retro_run only refreshes the framebuffer (src/retro/main_retro.c:190-193, src/retro/main_retro.c:286-299). The name is fixed by that check: the .rom and .tos fallbacks of File_Read (src/tos.c:60-66, src/file.c:312-353, src/file.c:544-583) are never reached under a frontend. A missing --tos file fails option parsing (src/options.c:1026-1079, src/options.c:1937-1945), but Main_ErrorExit only raises the quit flag in this build (src/retro/main_retro.c:529-541), so Main_Init carries on with bUseTos cleared and TOS_InitImage installs the built-in test stub of faketosData.c instead of reading a ROM (src/tos.c:43, src/tos.c:1112-1131, src/tos.c:1151-1162). Without a system directory Main_Init runs with no --tos, the TOS path falls back to tos.img in the Hatari data directory derived from the executable location (src/configuration.c:810-812, src/paths.c:305-356, CMakeLists.txt:422-434) and have_bios is never set. TOS_LoadImage strips the 256-byte (34-byte for 4.92) loader of a RAM TOS, detects EmuTOS by ETOS at offset 0x2c, refuses images below 0x40 bytes, above 1 MB, with a version outside 0x100-0x6FF or a load address other than 0xE00000 or 0xFC0000, and coerces machine type and CPU to the TOS version unless the image is a 512 KB or larger EmuTOS (src/tos.c:976-1097, src/tos.c:838-969). ROM patches apply when the hatari_patch_tos option is on and the image is not EmuTOS (src/retro/options.c:252-265, src/retro/options.c:877, src/tos.c:1220-1222). No TOS is embedded. Because nSymbolsAutoLoad defaults to SYM_AUTOLOAD_DEBUGGER (src/configuration.c:621, src/includes/configuration.h:29-31), every TOS load also reads a <tos>.sym symbol table when one exists (src/tos.c:1094, src/debug/symbols.c:1095-1113, src/debug/symbols.c:1002-1020, src/debug/symbols.c:372-407).

The Hatari home directory is the RetroArch save directory (src/paths.c:236-250). Configuration is read from <CONFDIR>/hatari.cfg, /etc on Unix and the current directory on Windows, then from hatari.cfg in that home directory, before the --tos argument is applied (src/main.c:260-282, src/main.c:319-322, src/configuration.c:862-867, src/configuration.c:1061-1071, CMakeLists.txt:444-461). The boot core options are applied right after the command line, so the machine, DSP, CPU, FPU, memory and hatari_patch_tos keys of hatari.cfg are overwritten by them (src/main.c:328-330, src/retro/options.c:817-882). Every other section is honoured: the cartridge image (src/configuration.c:487-493), floppy images, GEMDOS directories and ACSI, SCSI and IDE images (src/configuration.c:362-364, src/configuration.c:375-483), MIDI, printer, RS232 and SCC host endpoints (src/configuration.c:509-543), all disabled by default (src/configuration.c:736-761) and opened by Midi_Host_Open, Printer_TransferByteTo, RS232_OpenCOMPort and SCC_Init_Channel when enabled (src/midi.c:342-367, src/printer.c:42-65, src/printer.c:89-106, src/rs232.c:175-246, src/scc.c:439-500). szMappingFileName is parsed (src/configuration.c:256) but the port's Keymap_LoadRemapFile is empty (src/retro/keymap.c:222-224). Only the SDL build reads a keymap file (src/sdl/keymap.c:701). The autosave snapshot is restored by M68000_Start (src/m68000.c:332-348), which the port never calls. TT and Falcon NVRAM is hatari.nvram in the home directory, read at NvRam_Init and written at exit (src/falcon/nvram.c:282-294, src/falcon/nvram.c:334-337).

Content is a floppy image, an .m3u list parsed relative to its own directory (src/retro/disk_control.c:94-182), an .ide image put on the IDE master, a .vhd image put on ACSI 0 or a .gem marker naming a GEMDOS directory (src/retro/main_retro.c:420-478, src/retro/harddisk.c:32-129). With a .gem, <system>/hatari/BOOT.ST is inserted into drive A when it exists (src/retro/harddisk.c:105-127). A disk whose name ends in A pulls the sibling ending in B into drive B (src/floppy.c:300-343, src/floppy.c:385-388), and an STX image reads its .wd1772 overlay from the same directory (src/floppies/stx.c:807-827). Savestates pass through hatari_savestate.tmp in the system directory (src/retro/main_retro.c:44, src/retro/main_retro.c:343-410). IPF support is compiled in from rsn8887/capsimg when ENABLE_STATIC_CAPSIMAGE is on (cmake/BuildDependencies.cmake:93-126). The Windows jobs build with it since September 2026 (.gitlab-ci-libretro.yml:101, .gitlab-ci-libretro.yml:109) and the static Vita, Wii, Wii U and Switch jobs turn it off (.gitlab-ci-libretro.yml:193, .gitlab-ci-libretro.yml:202, .gitlab-ci-libretro.yml:210, .gitlab-ci-libretro.yml:218). File access goes through the libretro VFS when the frontend provides it (src/retro/vfs.c:17-48, src/file.c:253-302, src/file.c:479-492), and a device-prefixed path such as ux0:/ counts as absolute (src/file.c:152-164).

The standalone program is the SDL build of the upstream tree. Its default TOS image is tos.img in the data directory (src/configuration.c:810-812), which is the directory of the executable on Windows, ../Resources in the macOS bundle and ../share/hatari beside the bin directory elsewhere (src/paths.c:316-330, CMakeLists.txt:383-394). --tos and the szTosImageFileName key replace it. When no image loads, Main_InitSubsystems opens the settings dialog to pick one and exits with Failed to load TOS image if none is chosen (src/main.c:191-201). Nothing is compiled in as a fallback. The install rule copies a src/tos.img into the data directory when one is present at build time, the source tree carries none, and the release checklist puts the latest EmuTOS 1024k image in the binary packages (doc/release-checklist.txt:85-86). The Hatari home directory is ~/.config/hatari, Library/Application Support/Hatari or AppData\Local\Hatari under the user's home (src/paths.c:24-29, src/paths.c:201-274). hatari.cfg is read from <CONFDIR> and then from that home directory, or from the file -c names (src/main.c:256-278, src/configuration.c:862-867, src/options.c:1283-1289). hatari.nvram and auto.sav, restored only when bAutoSave is on, are kept there (src/configuration.c:727-733). The window icon is hatari-icon.bmp in the data directory (src/sdl/screen.c:711-720). --lilo boots a Linux kernel instead of TOS, vmlinuz and initrd in the data directory by default (src/configuration.c:816-824, src/options.c:2309-2323). IPF images are decoded by the built-in reader unless the capsimage library is found at build time, which then reads them, and RAW and CTR images need that library (src/CMakeLists.txt:70-74, CMakeLists.txt:185-188).

Files

Section titled “Files”

9 files: 1 required, 8 optional.

In this collection: 2 in repo, 2 missing and 5 unsourceable.

Required

Section titled “Required”
FileStatus

tos.img

Atari TOS ROM image

  • Any TOS 1.00 to 4.04, TOS 0.00, a RAM TOS or EmuTOS. The file must carry this exact name in the libretro build: retro_init only enables emulation when <system>/tos.img exists. The standalone program opens tos.img in its data directory unless --tos or the szTosImageFileName key of hatari.cfg names another file. A missing name is retried with its extension replaced by .img, .rom and .tos, so tos.rom and tos.tos stand in for the default, and a .gz or archive is unpacked first. The program exits when no image loads and none is picked in the settings dialog (src/options.c:1937-1940, src/configuration.c:489, src/tos.c:983, src/main.c:191-201).
Validation and source
in repo

Optional

Section titled “Optional”
FileStatusHash

tos.sym

Symbol table for the TOS image, nm-style text or a program symbol table

  • The name is the TOS image path with its last three characters replaced by sym, and the image path is always tos.img here: retro_init passes <system>/tos.img as --tos and no other image name reaches the loader, so a table named after another image, emutos.sym beside emutos.img, is never opened. nSymbolsAutoLoad gates the read. Its default is not off and no core option changes it, so the table is read at every TOS load when present. The standalone program derives the name the same way from the image it opens, tos.sym beside the default tos.img in its data directory. The symbols serve the built-in debugger.

  • Not collectable: one table per TOS build, valid only beside the image it was linked with: each EmuTOS release archive carries the table of its ROM, etos512k.sym beside etos512k.img, and Atari TOS has none (acknowledged gaps)

Source
unsourceable user_provided-

floppy.raw

Floppy drive sample, signed 16-bit little-endian stereo at 44100 Hz, no header

  • Read whole at retro_init when its size is between 4 bytes and 16 MB, and resampled to the core's audio rate. Otherwise the built-in synthesised sound plays (src/retro/floppy_sound.c:48-101). Played when a drive LED comes on while hatari_floppy_sound is enabled, its default.

  • Not collectable: any headerless s16le stereo 44100 Hz sample the user records, with no name or version the code expects beyond the filename (acknowledged gaps)

  • Size: min 4 B, max 16.0 MB
Validation and source
unsourceable libretro user_provided built-in fallback-

cartridge ROM

Atari ST cartridge image loaded at 0xFA0000

  • Set through hatari.cfg, or with --cartridge in the standalone program. Raw images up to 0x20000 bytes or .stc images of exactly 0x20004 bytes whose 4-byte header is skipped. Extensions .img, .rom and .stc are tried when the configured path is missing. Replaced by the built-in GEMDOS trampoline whenever GEMDOS hard disk emulation, extended VDI, program autostart or OS tracing is on.
  • Size: min 40 B, max 128.0 KB
Validation, source and config key
  • Config key: szCartridgeImageFileName
missing-

BOOT.ST

Boot floppy inserted with GEMDOS hard disk folders

  • Path: hatari/BOOT.ST
  • Inserted into drive A when the content is a .gem file.
Source
in repo libretro-

hatari.cfg

Hatari configuration file

  • Standalone path: hatari.cfg, in the data folder

  • Read from <CONFDIR>/hatari.cfg and then from hatari.cfg in the RetroArch save directory, before the --tos argument and the boot core options are applied. The standalone program reads the second file from its home directory, ~/.config/hatari on Linux, or from the file -c names.

  • Not collectable: user settings in Hatari's INI format, with no canonical contents (acknowledged gaps)

Source
unsourceable user_provided-

hatari.nvram

TT and Falcon NVRAM contents, 50 bytes

  • Standalone path: hatari.nvram, in the data folder

  • Read from the RetroArch save directory at NvRam_Init, and from the Hatari home directory in the standalone program. A short read keeps the built-in defaults. Saved back on exit.

  • Not collectable: machine state the emulator writes itself at exit, with no canonical contents (acknowledged gaps)

  • Size: min 50 B
Validation and source
unsourceable user_provided built-in fallback-

keymap file

Host key to ST scancode remapping table, text

  • Named by --keymap or the szMappingFileName key, empty by default. Read at start and again when the setting changes. A missing file logs a warning and keeps the default mapping.

  • Not collectable: user settings in Hatari's keymap text format, with no canonical contents (acknowledged gaps)

Source and config key
  • Config key: szMappingFileName
unsourceable standalone user_provided-

hatari-icon.bmp

Window icon

  • Loaded with SDL_LoadBMP from the data directory when the window is created. Without it the window keeps the default icon. Installed from src/hatari-icon.bmp, whose hashes these are.
  • Size: 630 B, SHA1 48be1de23a98
Hashes and source
  • SHA1: 48be1de23a980bca15a8ed3cb92917340e43bbee
  • MD5: f5e9c46fbbdc660d024a1bdd286a05ef
  • CRC32: 1639262c
  • SHA256: 0e083a340ad2e522de94e5121565a4730f99d6ee3638c74f5a2c3be579529155
  • Asked for by: upstream emulator
  • Source: src/sdl/screen.c:711-720 (upstream emulator), src/CMakeLists.txt:391-394 (upstream emulator)
missing standalone installed with the standalone emulatorMD5 f5e9c46fbbdc

Next steps

Section titled “Next steps”
.

Maintained by Abdess on GitHub. Report a problem.

Packs from release v2026.10.10, .

MIT for the tooling and metadata. BIOS and firmware files are third-party system software, preserved for personal backup, archival and interoperability.