Flipper Zero Firmware
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Flipper Build Tool

FBT is the entry point for firmware-related commands and utilities. It is invoked by ./fbt in the firmware project root directory. Internally, it is a wrapper around scons build system.

If you don't need all features of fbt - like building the whole firmware - and only want to build and debug a single application, you can use ufbt.


To use fbt, you only need git installed in your system.

fbt by default downloads and unpacks a pre-built toolchain, and then modifies environment variables for itself to use it. It does not contaminate your global system's path with the toolchain.

‍However, if you wish to use tools supplied with the toolchain outside fbt, you can open an fbt shell, with properly configured environment.

  • On Windows, simply run scripts/toolchain/fbtenv.cmd.
  • On Linux & MacOS, run source scripts/toolchain/fbtenv.sh in a new shell.
  • You can also type . `./fbt -s env` in your shell. (Keep the "." at the beginning.)

If your system is not supported by pre-built toolchain variants or you want to use custom versions of dependencies, you can set FBT_NOENV=1. fbt will skip toolchain & environment configuration and will expect all tools to be available on your system's PATH. *(this option is not available on Windows)*

If FBT_TOOLCHAIN_PATH variable is set, fbt will use that directory to unpack toolchain into. By default, it downloads toolchain into toolchain subdirectory repo's root.

If you want to enable extra debug output for fbt and toolchain management scripts, you can set FBT_VERBOSE=1.

fbt always performs git submodule update --init on start, unless you set FBT_NO_SYNC=1 in the environment:

  • On Windows, it's set "FBT_NO_SYNC=1" in the shell you're running fbt from
  • On *nix, it's $ FBT_NO_SYNC=1 ./fbt ...

‍There are more variables controlling basic fbt behavior. See fbt & fbtenv scripts' sources for details.

Invoking FBT

To build with FBT, call it and specify configuration options & targets to build. For example:

./fbt COMPACT=1 DEBUG=0 VERBOSE=1 updater_package copro_dist

To run cleanup (think of make clean) for specified targets, add the -c option.

Build directories

fbt builds updater & firmware in separate subdirectories in build, and their names depend on optimization settings (COMPACT & DEBUG options). However, for ease of integration with IDEs, the latest built variant's directory is always linked as built/latest. Additionally, compile_commands.json is generated in that folder (it is used for code completion support in IDEs).

build/latest symlink & compilation database are only updated upon firmware build targets - that is, when you're re-building the firmware itself. Running other tasks, like firmware flashing or building update bundles for a different debug/release configuration or hardware target, does not update built/latest dir to point to that configuration.

VSCode integration

fbt includes basic development environment configuration for VS Code. Run ./fbt vscode_dist to deploy it. That will copy the initial environment configuration to the .vscode folder. After that, you can use that configuration by starting VS Code and choosing the firmware root folder in the "File > Open Folder" menu.

To use language servers other than the default VS Code C/C++ language server, use ./fbt vscode_dist LANG_SERVER=<language-server> instead. Currently fbt supports the default language server (cpptools) and clangd.

  • On the first start, you'll be prompted to install recommended plugins. We highly recommend installing them for the best development experience. You can find a list of them in .vscode/extensions.json.
  • Basic build tasks are invoked in the Ctrl+Shift+B menu.
  • Debugging requires a supported probe. That includes:
    • Wi-Fi devboard with stock firmware (blackmagic).
    • ST-Link and compatible devices.
    • J-Link for flashing and debugging (in VSCode only). Note that J-Link tools are not included with our toolchain and you have to download them yourself and put them on your system's PATH.
  • Without a supported probe, you can install firmware on Flipper using the USB installation method.

FBT targets

fbt keeps track of internal dependencies, so you only need to build the highest-level target you need, and fbt will make sure everything they depend on is up-to-date.

High-level (what you most likely need)

  • fw_dist - build & publish firmware to the dist folder. This is a default target when no others are specified.
  • fap_dist - build external plugins & publish to the dist folder.
  • updater_package, updater_minpackage - build a self-update package. The minimal version only includes the firmware's DFU file; the full version also includes a radio stack & resources for the SD card.
  • copro_dist - bundle Core2 FUS+stack binaries for qFlipper.
  • flash - flash the attached device over SWD interface with supported probes. Probe is detected automatically; you can override it with SWD_TRANSPORT=... variable. If multiple probes are attached, you can specify the serial number of the probe to use with SWD_TRANSPORT_SERIAL=....
  • flash_usb, flash_usb_full - build, upload and install the update package to the device over USB. See details on updater_package and updater_minpackage.
  • debug - build and flash firmware, then attach with gdb with firmware's .elf loaded.
  • debug_other, debug_other_blackmagic - attach GDB without loading any .elf. It will allow you to manually add external .elf files with add-symbol-file in GDB.
  • updater_debug - attach GDB with the updater's .elf loaded.
  • devboard_flash - Update WiFi dev board. Supports ARGS="..." to pass extra arguments to the update script, e.g. ARGS="-c dev".
  • blackmagic - debug firmware with Blackmagic probe (WiFi dev board).
  • openocd - just start OpenOCD. You can pass extra arguments with ARGS="...".
  • get_blackmagic - output the blackmagic address in the GDB remote format. Useful for IDE integration.
  • get_stlink - output serial numbers for attached STLink probes. Used for specifying an adapter with SWD_TRANSPORT_SERIAL=....
  • lint, format - run clang-format on the C source code to check and reformat it according to the .clang-format specs. Supports ARGS="..." to pass extra arguments to clang-format.
  • lint_py, format_py - run black on the Python source code, build system files & application manifests. Supports ARGS="..." to pass extra arguments to black.
  • firmware_pvs - generate a PVS Studio report for the firmware. Requires PVS Studio to be available on your system's PATH.
  • doxygen - generate Doxygen documentation for the firmware. doxy target also opens web browser to view the generated documentation.
  • cli - start a Flipper CLI session over USB.

Firmware targets

  • faps - build all external & plugin apps as .faps.
  • fbt also defines per-app targets. For example, for an app with appid=snake_game target names are:
    • fap_snake_game, etc. - build single app as .fap by its application ID.
    • Check out `--extra-ext-apps` for force adding extra apps to external build.
    • fap_snake_game_list, etc - generate source + assembler listing for app's .fap.
  • flash, firmware_flash - flash the current version to the attached device over SWD.
  • jflash - flash the current version to the attached device with JFlash using a J-Link probe. The JFlash executable must be on your $PATH.
  • firmware_all, updater_all - build a basic set of binaries.
  • firmware_list, updater_list - generate source + assembler listing.
  • firmware_cdb, updater_cdb - generate a compilation_database.json file for external tools and IDEs. It can be created without actually building the firmware.


  • resources - build resources and their manifest files
    • dolphin_ext - process dolphin animations for the SD card
  • icons - generate .c+.h for icons from PNG assets
  • proto - generate .pb.c+.pb.h for .proto sources
  • proto_ver - generate .h with a protobuf version
  • dolphin_internal, dolphin_blocking - generate .c+.h for corresponding dolphin assets

Command-line parameters

  • --options optionfile.py (default value fbt_options.py) - load a file with multiple configuration values
  • --extra-int-apps=app1,app2,appN - force listed apps to be built as internal with the firmware target
  • --extra-ext-apps=app1,app2,appN - force listed apps to be built as external with the firmware_extapps target
  • --extra-define=A --extra-define=B=C - extra global defines that will be passed to the C/C++ compiler, can be specified multiple times
  • --proxy-env=VAR1,VAR2 - additional environment variables to expose to subprocesses spawned by fbt. By default, fbt sanitizes the execution environment and doesn't forward all inherited environment variables. You can find the list of variables that are always forwarded in the environ.scons file.


Default configuration variables are set in the configuration file: fbt_options.py. Values set in the command line have higher precedence over the configuration file.

You can also create a file called fbt_options_local.py that will be evaluated when loading default options file, enabling persisent overriding of default options without modifying default configuration.

You can find out available options with ./fbt -h.

Firmware application set

You can create customized firmware builds by modifying the list of applications to be included in the build. Application presets are configured with the FIRMWARE_APPS option, which is a map(configuration_name:str -> application_list:tuple(str)). To specify an application set to use in the build, set FIRMWARE_APP_SET to its name. For example, to build a firmware image with unit tests, run ./fbt FIRMWARE_APP_SET=unit_tests.

Check out fbt_options.py for details.