Copter-3.6.9-rc2 available for beta testing

Although it has only been a few days since Copter-3.6.8 was released, we have a new 3.6.9-rc2 beta version that is available for testing and should appear in the ground stations’s Beta Firmwares link within a few hours.

These are minor bug fixes and enhancements.

The changes can be seen in the ReleaseNotes and are also copied below.

Changes from 3.6.8

  1. CX-OF flow sensor enabled on all boards
  2. CUAVv5 Nano board support added
  3. RangeFinders supported on all I2C ports
  4. Compass maximum acceptable offsets increased
  5. Septentrio GPS driver loses logging of camera feedback which could cause lag
  6. Bug Fixes:
    a) Acro mode leveling fix for when ACRO_TRAINER was 1
    b) Tradheli collective position pre-arm check removed
    c) Fallback to microSD for storage fixed
    d) GPS blending memory access fix that could lead to unhealthy GPS

Thanks very much in advance for any testing people can do!

P.S. in case you are wondering, “what happened to 3.6.9-rc1?”, immediately after releasing -rc1 I realised I’d missed item 4 (increase in acceptable compass offsets) so I went back and added it.


Hello Randy,

Thank you and thank to all ardupilot dev team for this work!

I need to start and take off my little quadrotor from my zodiak on sea.

What is needed to achieve this without prearm issues?

And does arducopter handle this feature safely?

Hi @kuspower,

So we call this “Boat Mode” and it’s here on the wiki. In theory it should just work but you may need to trigger the gyro calibration again manually (see “Manually trigger gyro calibration” on the above link). It also possible to disable the gyro cal by setting INS_GYR_CAL = 0.

Thank you for your quick reply.

does ek2 is able to do inflight calibration?

How does it work?

@kuspower, my understanding is the EKF compares the gyros to the accelerometer and compass and then it slowly adds a “bias” to make them agree with each other.

It might be a good idea to try it on land first to see if it will work before trying it from the Zodiac. Try plugging in the battery while the vehicle is moving a bit - perhaps place it on a swing and see how it does…

At the moment everything works perfectly, I performed more tests (2 days of vacation :wink:) and I can only confirm the excellent work done by the developers … Tests carried out on Radiolink minipix, Matek F405Std and Pixhawk PX4. I also confirm that the Cx-of works perfectly without the need to force the drivers.

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eta on this release? was about to do 3.6.8 until i saw this… there’s always lots of anxiety upgrading firmware and making sure all parameters “take” so maybe I’ll just wait for this to release


Great, thanks very much for the feedback especially re the CX-OF.


I think 3.6.9 will go out some time next week. Before then there will be a 3.6.9-rc3 I’m afraid because we’ve got another fix for fmuv5 boards (which I think are the new STM32F7 boards) logging of power coming in from the 2nd power module input.

If the vehicle is being upgraded from 3.6.x, the upgrade to 3.6.8 or 3.6.9 should be really painless. No need for re-calibration, re-tuning or backing up of parameters. It should just work without any issues I would have thought.

ok ill try loading 3.6.8 without loading rover first and see what happens

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i’m not getting a chibios option anymore… is chibios forced now?

@Iketh, 3.6.x should be available for both ChibiOS and NuttX. I’ve just done a test with latest Beta Mission Planner (Mission Planner 1.3.66 build 1.3.7058.42200) uploading to an mRobotics Pixhawk and it popped up the “ChibiOS?” question and I tested loading both ChibiOS or NuttX (one after the other) and it seemed to work.

As a side note, there have certainly been a number of issues with MP having trouble working out which firmware to load so we’ve been working MichaelO to improve the situation in a few ways:

  • we’ve created a “manifest” file which creates a mapping between the flight controller’s bootloader id and a location on where the appropriate firmware can be found.
  • we’ve asked MichaelOborne to provide a drop-down so users can select from a list of firmwares instead of answering a series of Yes/No questions (issue here)
  • store all older firmwares on (i.e. items available through the “Pick previous firmware” were stored in a special MP repo instead of on the central ardupilot server)

I can’t get MP to ask for chibios… i’ve updated to .8 and .9-rc2 and no idea what OS im using

i have been nuttx but want to go chibi since in that bulletin it is stated nuttx is no longer supported, but now no chibios question…

Looks like Cheerson do not want to sell CX-OF module as a separately part now. Hope Arducopter will have more flow drivers, Thanks!

@bys_1123, my guess is the HereFlow will become the most popular because it will have a more guaranteed supply and it is easy to connect and use. We don’t pick hardware winners on the AP software side though - we are happy to integrate and release more drivers as developers create them.

You’re right, I bought the HereFlow from Proficnc, I think it will be a better alternative.
I am eager to see the release of Copter-3.7.0-beta to take advantage of the hereFlow optical sensor capability.

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i got the chibios question to pop up by answering NO to is this a cube black… so is answering yes defaulting to chibios now? anyone know?