Flight Core Firmware (Work in Progress)


Flight Core

Although Flight Core is supported in PX4 Mainline starting with 1.10, we’ve addressed several issues which didn’t make it into the release.

For v1.10, it’s recommended that you use the ModalAI build:

This can be built for yourself as well:

git clone https://github.com/modalai/px4-firmware
cd px4-firmware
git checkout modalai-1.10
make modalai_fc-v1

Here are the .px4 files generated from PX4’s CI servers, which are generated from the PX4 beta and master branches:

Flying Flight Core Indoors with VIO from VOXL

We have a branch of Flight Core Firmware setup for indoor flight with voxl-vision-px4 as described here. The branch is located here: modalai-1.10-ekf2-init-vio

The modalai-1.10-ekf2-init-vio branch combines:

with an updated ECL library forked in our github:

This branch simply allows EKF2 to initialize without magnetometer data if there is EV (external vision) data available instead. This is currently considered a test branch and we will try to get a pull reqeust into the ECL library.


Nearly identical besides start up configuration, the firmware for VOXL-Flight configuration is available PX4 mainline in the master branch. At this time, the only difference is to handle the physical serial port connection now routed in the PCB.

Changelog / Known Issues

The following describe known issues and changes that are related to the Flight Core + VOXL or VOXL-Flight systems with respect to PX4.

PX4 v1.10

The following are known issues in the PX4 built 1.10, which are fixed in the master branch of PX4, and are fixed in the 1.10 build referenced above.

  • A ROTATION_YAW_180 orientation is required for the typical configuration when paired with VOXL (e.g. cameras in front on vehicle)
  • Stack size issue with bmp388 driver
  • SD Card logging issues
  • In order for EKF to initialize, it requires magnetometer readings (still present in ModalAI built 1.10)

ModalAI Forks


The ModalAI forks used for development are maintained here:

GitLab CI

The two repos above have CI on the ModalAI GitLab servers here:

How to Build the Firwmare

This example uses the PX4 mainline repository.

git clone https://github.com/PX4/Firmware.git
cd Firmware
make modalai_fc-v1

You can use JFlash with a .jlink file with command like so, where deadbeef.bin is the name of the binary file:

loadbin deadbeef.bin,0x08008000