When will ChibiOS replace NutX

It looks like NutX is dead and we are switching to ChibiOS as an operating system.

If that is the case will the next release of ArduPilot be version 4.0 or 4.5 to show that it is on ChibiOS or will it be just another minor fix like 3.7.

It seem that getting it for PixRacer or Pixhawk is not going to be anytime soon since other hardware is being worked on.

So is there a way to build are own versions of the code for PixRacer or Pixhawk?

@iseries Nuttx builds are not dead and is still the primary RTOS for Ardupilot’s Microcontroller based platforms.
Also, pixhawk and pixracer builds with ChibiOS are already supported, you can build by setting the board as fmuv3 for pixhawk, pixhawk cube and other related boards with IO controllers, and pixracer using fmuv4 option.
So it will look like this:

./waf configure --board fmuv3
./waf plane
./waf --target bin/arducopter

There are several other boards you can choose between, do ./waf --help to see or checkout this link https://github.com/ArduPilot/ardupilot/tree/master/libraries/AP_HAL_ChibiOS/hwdef . Feel free to report failures on the gitter channel https://gitter.im/ArduPilot/ChibiOS .

Warning: The ChibiOS port is undergoing heavy development and hasn’t been tested as widely, so strict caution is to be taken when flight tests based on Ardupilot ChibiOS ports are done.

So, what you are saying is that there is no Beta release of ChibiOS right now and you have to build your own if you want to use it.

While ChibiOS may be a better RTOS for ArduPilot then NutX at the end of the day it provides no value to current customers.

Will it support Beta Flight F4 controllers?


There is a benefit. Many people are limited to 1mb flash. This has already been reached effectively in current Master so ChibOS will keep this hardware running without removing features in future releases.

In addition will allow more/newer simultaneous EKFs etc to be run.

Semantic point. We are not customers. We are users in a open source project!

Right, didn’t pay anything for this product or does Blood, Sweet and Tears count.


Sometimes, total destruction of the vehicle is considered as an additionnal fee for beta testers…


Chibios is still a work in progress. You can use it to the extent that it is currently implemented as described above. Like any other new feature in progress, you’re a test pilot if you use it. As of a few weeks ago, it was not likely that Chibios would be complete and ready to replace NuttX in the production stable release of 3.6.0.

I don’t mind being a test pilot but a do mind having to compile it myself.

It’s not clear how to get from Nutx to ChibiOS.

I built a Ubuntu server in the cloud and tried building PixRacer for ChibiOS and it doesn’t work with the current master. endian.h and byteswap.h are missing when I configure fmuv4.


And major performance improvements, along with easier ports :wink:

I suppose having Chibios builds compiled and available on the firmware server will start happening once Tridge and others are comfortable enough with its stability and reliability. Making it readily available for people to easily download and install is a double edged sword. It makes it easy, but sometimes too easy for people who are not prepared or capable of being a test pilot.

If there is a problem with the builder, that is probably easy enough for Tridge to fix. But I would expect to continue having to run the build yourself until it is a little less experimental.

There’s still a few ( minor) feature/s that aren’t considered “ready” yet… so it’s not feature complete yet, and it’s important not to break existing features during a transition like this…

What are those features not considered ready for fmuv2 and fmuv3 ?
Could you list them, please?


you will have some clues here : https://github.com/ArduPilot/ardupilot/pull/7851