# UAVCAN error in FC v2 px4 firmware

Source: https://forum.modalai.com/topic/5264/uavcan-error-in-fc-v2-px4-firmware
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2026-06-15 15:27:31 UTC by Jetson Nano
Replies: 4 · Views: 671

## Jetson Nano · 2026-06-15 15:27:31 UTC

@Eric-Katzfey @Alex-Kushleyev

I have the ark flow MR attached to the FC. While I want to check the standard builds, the standard build do not have UAVCAN modules enabled. i have to enable them manually.

If anyone could share the built px4 file for the ModalAi FC v2 along with UAVCAN enabled and collision prevention working, It would mean alot.

## Reply by Eric Katzfey (ModalAI staff) · 2026-06-15 16:04:39 UTC

@Jetson-Nano Which build, specifically, are you looking for? Something from the ModalAI fork of PX4 or from mainline? Are you not able to build firmware yourself?

## Reply by Jetson Nano · 2026-06-15 16:36:07 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 
I am able to build, my build is not able to have both collision prevention and uavcan working. if i go to the latest version the hearding error is showing up, prearm check is not passing.

I checked with px4 mainline as well as modalai fork, 

branches including - voxl-fpv-dev, version 1.17-dev
main branches - release/1.17, 1.16, 1.15

None of the above have the UAVCAN enabled, I do it manually, and the UAVCAN error is solved.

If you could guide me to a version of PX4 where both of this works with Flight core v2, or share the px4 build, if you have it working, i could test it out .

## Reply by Eric Katzfey (ModalAI staff) · 2026-06-16 16:02:54 UTC (in reply to Jetson Nano)

@Jetson-Nano So you can get UAVCAN working? And we are working through the collision prevention in the other post. But you say that there is a "hearding error"? I'm guessing you mean a heading error? Do you have GPS / Mag enabled? Can you try the tip of mainline? There have been some recent updates to get rid of the heading error when using only a vision based position estimate.

## Reply by Jetson Nano · 2026-06-16 16:20:53 UTC (in reply to Eric Katzfey)

@Eric-Katzfey UAVCAN is working in the latest versions, when enabled. And yes I meant heading error, thats my mistake.
The collision prevention is the major issue I am having. 
The heading error is in the latest version, and I also came across it in the issues section and it was shown solved, but I did not test it out still with VIO, I was testing with only Optical flow and it was not working.