Building PX4 Software

PX4 can be built on the console or in an IDE, for both simulated and hardware targets.

Before following these instructions you must first install the Developer Toolchain for your host operating system and target hardware.

For solutions to common build problems see Troubleshooting below.

Downloading PX4 Source Code

The PX4 source code is stored on Github in the PX4/Firmware repository. We recommend that you fork this repository (creating a copy associated with your own Github account), and then clone the source to your local computer.

Forking the repository allows you to better manage your custom code. Later on you will be able to use git to share changes with the main project.

The steps to fork and clone the project source code are:

  1. Sign up to Github.
  2. Go to the Firmware repository and click the Fork button near the upper right corner. This will create and open the forked repository.

    Github Fork button

  3. Copy the repository URL for your Firmware repository fork. The easiest way to do this is to click the Clone or download button and then copy the URL:

    Github Clone or download button

  4. Open a command prompt/terminal on your computer
    • On OS X, hit ⌘-space and search for 'terminal'.
    • On Ubuntu, click the launch bar and search for 'terminal'.
    • On Windows, find the PX4 folder in the start menu and click on 'PX4 Console'.
  5. Clone the repository fork using the copied URL. This will look something like:

    git clone<youraccountname>/Firmware.git

    If you're just experimenting (and don't want to make any sort of permanent changes) you can simply clone the main Firmware repository as shown:

     git clone

    Windows users refer to the Github help. You can use a git command line client as above or instead perform the same actions with the Github for Windows app.

This will copy most of the very latest version of PX4 source code onto your computer (the rest of the code is automatically fetched from other git submodules when you build PX4).

Get a Specific Release

To get the source code for a specific older release:

  1. Clone the Firmware repo and navigate into Firmware directory:
    git clone
    cd Firmware
  2. List all releases (tags)
    git tag -l
  3. Checkout code for particular tag (e.g. for tag 1.7.4beta)
    git checkout v1.7.4beta

First Build (Using the jMAVSim Simulator)

For the first build we'll build for a simulated target using a console environment. This allows us to validate the system setup before moving on to real hardware and an IDE.

Navigate into the Firmware directory and start jMAVSim using the following command:

make px4_sitl jmavsim

This will bring up the PX4 console below:

PX4 Console (jMAVSim)

The drone can be flown by typing:

pxh> commander takeoff


The drone can be landed by typing commander land and the whole simulation can be stopped by doing CTRL+C (or by entering shutdown).

Flying the simulation with the ground control station is closer to the real operation of the vehicle. Click on a location in the map while the vehicle is flying (takeoff flight mode) and enable the slider. This will reposition the vehicle.

QGroundControl GoTo

PX4 can be used with a number of other Simulators, including Gazebo Simulation and AirSim Simulation. These are also started with make - e.g.

  make px4_sitl gazebo

NuttX / Pixhawk Based Boards


To build for NuttX- or Pixhawk- based boards, navigate into the Firmware directory and then call make with the build target for your board.

For example, to build for Pixracer you would use the following command:

cd Firmware
make px4_fmu-v4_default

In the example above the first part of the build target px4_fmu-v4 is the firmware for a particular flight controller hardware and default is the configuration name (in this case the "default" configuration). The default is optional so you could instead do:

  make px4_fmu-v4

A successful run will end with similar output to:

-- Build files have been written to: /home/youruser/src/Firmware/build/px4_fmu-v4_default
[954/954] Creating /home/youruser/src/Firmware/build/px4_fmu-v4_default/px4_fmu-v4_default.px4

The following list shows the build commands for common boards:

Generally the _default suffix is optional (i.e. you can also build using make px4_fmu-v4, make bitcraze_crazyflie, etc.).

Uploading Firmware (Flashing the board)

Append upload to the make commands to upload the compiled binary to the autopilot hardware via USB. For example

make px4_fmu-v4_default upload

A successful run will end with this output:

Erase  : [====================] 100.0%
Program: [====================] 100.0%
Verify : [====================] 100.0%

[100%] Built target upload

Other Boards

The following boards have more complicated build and/or deployment instructions.

Raspberry Pi 2/3 Boards

The command below builds the target for Raspberry Pi 2/3 Navio2.

Cross-compiler Build

Set the IP (or hostname) of your RPi using:

export AUTOPILOT_HOST=192.168.X.X


export AUTOPILOT_HOST=pi_hostname.domain

The value of the environment variable should be set before the build, or make upload will fail to find your RPi.

Build the executable file:

cd Firmware
make emlid_navio2_cross # for cross-compiler build

The "px4" executable file is in the directory build/emlid_navio2_cross/. Make sure you can connect to your RPi over ssh, see instructions how to access your RPi.

Then set the IP (or hostname) of your RPi using:

export AUTOPILOT_HOST=192.168.X.X

And upload it with:

cd Firmware
make emlid_navio2_cross upload # for cross-compiler build

Then, connect over ssh and run it with (as root):

sudo ./bin/px4 -s px4.config

Native Build

If you're building directly on the Pi, you will want the native build target (emlid_navio2_native).

cd Firmware
make emlid_navio2_native # for native build

The "px4" executable file is in the directory build/emlid_navio2_native/. Run it directly with:

sudo ./build/emlid_navio2_native/px4 -s ./posix-configs/rpi/px4.config

A successful build followed by executing px4 will give you something like this:

______  __   __    ___
| ___ \ \ \ / /   /   |
| |_/ /  \ V /   / /| |
|  __/   /   \  / /_| |
| |     / /^\ \ \___  |
\_|     \/   \/     |_/

px4 starting.



To autostart px4, add the following to the file /etc/rc.local (adjust it accordingly if you use native build), right before the exit 0 line:

cd /home/pi && ./bin/px4 -d -s px4.config > px4.log

Parrot Bebop

Support for the Parrot Bebop is at an early stage and should be used very carefully.


cd Firmware
make parrot_bebop

Turn on your Bebop and connect your host machine with the Bebop's wifi. Then, press the power button four times to enable ADB and to start the telnet daemon.

make parrot_bebop upload

This will upload the PX4 mainapp into /data/ftp/internal_000/px4/ and create the file /home/root/parameters if not already present. This also uploads the mixer file and the px4.config file into the /home/root/ directory.


Connect to the Bebop's wifi and press the power button four times. Next, connect with the Bebop via telnet or adb shell and run the commands below.


Kill the Bebop's proprietary driver with


and start the PX4 mainapp with:

/data/ftp/internal_000/px4/px4 -s /home/root/px4.config /data/ftp/internal_000/px4/

In order to fly the Bebop, connect a joystick device with your host machine and start QGroundControl. Both the Bebop and the joystick should be recognized. Follow the instructions to calibrate the sensors and setup your joystick device.


To auto-start PX4 on the Bebop at boot, modify the init script /etc/init.d/rcS_mode_default. Comment the following line: -out2null &

Replace it with:

echo 1 > /sys/class/gpio/gpio85/value # enables the fan
/data/ftp/internal_000/px4/px4 -d -s /home/root/px4.config /data/ftp/internal_000/px4/ >/dev/null &

Enable adb server by pressing the power button 4 times and connect to adb server as described before:

adb connect

Re-mount the system partition as writeable:

adb shell mount -o remount,rw /

In order to avoid editing the file manually, you can use this one:

Save the original one and push this one to the Bebop

adb shell cp /etc/init.d/rcS_mode_default /etc/init.d/rcS_mode_default_backup
adb push rcS_mode_default /etc/init.d/
adb shell chmod 755 /etc/init.d/rcS_mode_default

Sync and reboot:

adb shell sync
adb shell reboot

OcPoC-Zynq Mini

Build instructions for the OcPoC-Zynq Mini are covered in:

QuRT / Snapdragon Based Boards

This section shows how to build for the Qualcomm Snapdragon Flight.


If you use the Qualcomm ESC board (UART-based), then please follow their instructions here. If you use normal PWM-based ESCs boards, then you may continue to follow the instructions on this page.

The commands below build the targets for the Linux and the DSP side. Both executables communicate via muORB.

cd Firmware
make atlflight_eagle_default

To load the SW on the device, connect via USB cable and make sure the device is booted. Run this in a new terminal window:

adb shell

Go back to previous terminal and upload:

make atlflight_eagle_default upload

Note that this will also copy (and overwrite) the two config files mainapp.config and px4.config to the device. Those files are stored under /usr/share/data/adsp/px4.config and /home/linaro/mainapp.config respectively if you want to edit the startup scripts directly on your vehicle.

The mixer currently needs to be copied manually:

adb push ROMFS/px4fmu_common/mixers/quad_x.main.mix  /usr/share/data/adsp


Run the DSP debug monitor:


Note: alternatively, especially on Mac, you can also use nano-dm.

Go back to ADB shell and run px4:

cd /home/linaro
./px4 -s mainapp.config

Note that the px4 will stop as soon as you disconnect the USB cable (or if you ssh session is disconnected). To fly, you should make the px4 auto-start after boot.


To run the px4 as soon as the Snapdragon has booted, you can add the startup to rc.local:

Either edit the file /etc/rc.local directly on the Snapdragon:

adb shell
vim /etc/rc.local

Or copy the file to your computer, edit it locally, and copy it back:

adb pull /etc/rc.local
gedit rc.local
adb push rc.local /etc/rc.local

For the auto-start, add the following line before exit 0:

(cd /home/linaro && ./px4 -s mainapp.config > mainapp.log)

exit 0

Make sure that the rc.local is executable:

adb shell
chmod +x /etc/rc.local

Then reboot the Snapdragon:

adb reboot

Compiling in a Graphical IDE

The PX4 system supports Qt Creator, Eclipse and Sublime Text. Qt Creator is the most user-friendly variant and hence the only officially supported IDE. Unless an expert in Eclipse or Sublime, their use is discouraged. Hardcore users can find an Eclipse project and a Sublime project in the source tree.

Qt Creator Functionality

Qt creator offers clickable symbols, auto-completion of the complete codebase and building and flashing firmware.

Qt Creator on Linux

Before starting Qt Creator, the project file needs to be created:

cd ~/src/Firmware
mkdir ../Firmware-build
cd ../Firmware-build
cmake ../Firmware -G "CodeBlocks - Unix Makefiles"

Then load the CMakeLists.txt in the root firmware folder via File > Open File or Project (Select the CMakeLists.txt file).

After loading, the play button can be configured to run the project by selecting 'custom executable' in the run target configuration and entering 'make' as executable and 'upload' as argument.

Qt Creator on Windows

Windows has not been tested for PX4 development with Qt Creator.

Qt Creator on Mac OS

Before starting Qt Creator, the project file needs to be created:

cd ~/src/Firmware
mkdir -p build/creator
cd build/creator
cmake ../.. -G "CodeBlocks - Unix Makefiles"

That's it! Start Qt Creator, then complete the steps in the video below to set up the project to build.

PX4 Make Build Targets

The previous sections showed how you can call make to build a number of different targets, start simulators, use IDEs etc. This section shows how make options are constructed and how to find the available choices.

The full syntax to call make with a particular configuration and initialization file is:



  • VENDOR: The manufacturer of the board: px4, aerotenna, airmind, atlflight, auav, beaglebone, intel, nxp, parrot, etc. The vendor name for Pixhawk series boards is px4.
  • MODEL: The board model "model": sitl, fmu-v2, fmu-v3, fmu-v4, fmu-v5, navio2, etc.
  • VARIANT: Indicates particular configurations: e.g. rtps, lpe, which contain components that are not present in the default configuration. Most commonly this is default, and may be omitted.

You can get a list of all available CONFIGURATION_TARGET options using the command below:

  make list_config_targets


  • VIEWER: This is the simulator ("viewer") to launch and connect: gazebo, jmavsim
  • MODEL: The vehicle model to use (e.g. iris (default), rover, tailsitter, etc), which will be loaded by the simulator. The environment variable PX4_SIM_MODEL will be set to the selected model, which is then used in the startup script to select appropriate parameters.
  • DEBUGGER: Debugger to use: none (default), ide, gdb, lldb, ddd, valgrind, callgrind. For more information see Simulation Debugging.

You can get a list of all available VIEWER_MODEL_DEBUGGER options using the command below:

  make px4_sitl list_vmd_make_targets


  • Most of the values in the CONFIGURATION_TARGET and VIEWER_MODEL_DEBUGGER have defaults, and are hence optional. For example, gazebo is equivalent to gazebo_iris or gazebo_iris_none.
  • You can use three underscores if you want to specify a default value between two other settings. For example, gazebo___gdb is equivalent to gazebo_iris_gdb.
  • You can use a none value for VIEWER_MODEL_DEBUGGER to start PX4 and wait for a simulator. For example start PX4 using make px4_sitl_default none and jMAVSim using ./Tools/ -l.

The VENDOR_MODEL_VARIANT options map to particular cmake configuration files in the PX4 source tree under the /boards directory. Specifically VENDOR_MODEL_VARIANT maps to a configuration file boards/VENDOR/MODEL/VARIANT.cmake (e.g. px4_fmu-v5_default corresponds to boards/px4/fmu-v5/default.cmake).

Additional make targets are discussed in the following sections (list is not exhaustive):

Binary Size Profiling

The bloaty_compare_master build target allows you to get a better understanding of the impact of changes on code size. When it is used, the toolchain downloads the latest successful master build of a particular firmware and compares it to the local build (using the bloaty size profiler for binaries).

This can help analyse changes that (may) cause px4_fmu-v2_default to hit the 1MB flash limit.

Bloaty must be in your path and found at cmake configure time. The PX4 docker files install bloaty as shown:

git clone --recursive /tmp/bloaty \
    && cd /tmp/bloaty && cmake -GNinja . && ninja bloaty && cp bloaty /usr/local/bin/ \
    && rm -rf /tmp/*

The example below shows how you might see the impact of removing the mpu9250 driver from px4_fmu-v2_default. First it locally sets up a build without the driver:

 % git diff
diff --git a/boards/px4/fmu-v2/default.cmake b/boards/px4/fmu-v2/default.cmake
index 40d7778..2ce7972 100644
--- a/boards/px4/fmu-v2/default.cmake
+++ b/boards/px4/fmu-v2/default.cmake
@@ -36,7 +36,7 @@ px4_add_board(
-               imu/mpu9250
+               #imu/mpu9250
                #magnetometer # all available magnetometer drivers

Then use the make target, specifying the target build to compare (px4_fmu-v2_default in this case):

% make px4_fmu-v2_default bloaty_compare_master
     VM SIZE                                                                                        FILE SIZE
 --------------                                                                                  --------------
  [DEL]     -52 MPU9250::check_null_data(unsigned int*, unsigned char)                               -52  [DEL]
  [DEL]     -52 MPU9250::test_error()                                                                -52  [DEL]
  [DEL]     -52 MPU9250_gyro::MPU9250_gyro(MPU9250*, char const*)                                    -52  [DEL]
  [DEL]     -56 mpu9250::info(MPU9250_BUS)                                                           -56  [DEL]
  [DEL]     -56 mpu9250::regdump(MPU9250_BUS)                                                        -56  [DEL]
...                                        -336  [DEL]
  [DEL]    -344 MPU9250_mag::_measure(ak8963_regs)                                                  -344  [DEL]
  [DEL]    -684 MPU9250::MPU9250(device::Device*, device::Device*, char const*, char const*, cha    -684  [DEL]
  [DEL]    -684 MPU9250::init()                                                                     -684  [DEL]
  [DEL]   -1000 MPU9250::measure()                                                                 -1000  [DEL]
 -41.3%   -1011 [43 Others]                                                                        -1011 -41.3%
  -1.0% -1.05Ki [Unmapped]                                                                       +24.2Ki  +0.2%
  -1.0% -10.3Ki TOTAL                                                                            +14.9Ki  +0.1%

This shows that removing mpu9250 from px4_fmu-v2_default would save 10.3 kB of flash. It also shows the sizes of different pieces of the mpu9250 driver.

Firmware Version & Git Tags

The PX4 Firmware Version and Custom Firmware Version are published using the MAVLink AUTOPILOT_VERSION message, and displayed in the QGroundControl Setup > Summary airframe panel:

Firmware info

These are extracted at build time from the active git tag for your repo tree. The git tag should be formatted as <PX4-version>-<vendor-version> (e.g. the tag in the image above was set to v1.8.1-2.22.1).

If you use a different git tag format, versions information may not be displayed properly.


General Build Errors

Many build problems are caused by either mismatching submodules or an incompletely cleaned-up build environment. Updating the submodules and doing a distclean can fix these kinds of errors:

git submodule update --recursive
make distclean

Flash overflowed by XXX bytes

The region 'flash' overflowed by XXXX bytes error indicates that the firmware is too large for the target hardware platform. This is common for make px4_fmu-v2_default builds, where the flash size is limited to 1MB.

If you're building the vanilla master branch, the most likely cause is using an unsupported version of GCC. In this case, install the version specified in the Developer Toolchain instructions.

If building your own branch, it is possibly you have increased the firmware size over the 1MB limit. In this case you will need to remove any drivers/modules that you don't need from the build.

macOS: Too many open fileserror

MacOS allows a default maximum of 256 open files in all running processes. The PX4 build system opens a large number of files, so you may exceed this number.

The build toolchain will then report Too many open files for many files, as shown below:

/usr/local/Cellar/gcc-arm-none-eabi/20171218/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld: cannot find NuttX/nuttx/fs/libfs.a: Too many open files

The solution is to increase the maximum allowed number of open files (e.g. to 300). You can do this in the macOS Terminal for each session:

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