Copter-3.6.5 released!

Copter-3.6.5 has been released as the official stable version. The changes vs 3.6.4 are in the ReleaseNotes and copied below:

  1. RC input related fixes:
    a) Pixhawk4 SBUS input and Serial6 pin mapping conflict resolved
    b) RC DSM sync bug fix (channel 8 could temporarily become zero, ChibiOS only)
    c) Mode and Auxiliary switch range check to protect during FrSky SBUS failsafe recovery
    d) RC protocol decoding for SRXL, SUMD and ST24 extended to all boards including pixracer and ChibiOS-only boards
  1. Other fixes and minor enhancements:
    a) SD Card reliability improvement (BRD_SD_SLOWDOWN param) and allow re-inserting card after boot
    b) Pixhawk board LED fix (ChibiOS only)
    c) Follow mode reports target distance and heading to ground station
    d) Pixhawk4-mini safety switch and LED fix
    e) Bebop2 build fix
  1. DrotekP3 Pro support
  2. Cube Purple support

Thanks very much to the beta testers who put their copters at release testing this update and reported back their findings so we could (hopefully) make this another solid release.

If you find any issues please comment below or open up a new topic in this Copter-3.6 category, thanks!


Surprise!! No infamous { No I/O thread heart beat } or {Bad logging}

CHIBIOS and Arducopter 3.6.5 on an octo quad [Octa quad]

That is using the old 1GB slow micro SD card!! Go and figure!?

Still have to test on six other aircrafts but it looks very promising.
Great dev people around. Thanks to you guys! :slight_smile:


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Great news! @tridge put a lot of effort into trying to resolve the SD card reliability issues. I think the biggest change was that it tries multiple times to use the card soon after startup (instead of just once) and it also has some recovery logic now if the SD card is removed and re-inserted.

I have just installed the 3.6.5 stable on my Pixhawk 4.

I can now arm my copter even without a gps fix, although my prearm-check is set to ‘1’ which means it should actually check for gps before arming?!


Perhaps check the flight mode. If the vehicle is in Stabilize or Acro mode it is possible to arm and fly without a GPS lock. If it’s in another mode then could you download a dataflash log file and post it here?

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Maybe I’m wrong, but it seems to me that the logic when regardless of the current mode, the copter will not arm without GPS Fix, more correct…

Yes the copter was in stabilize mode. I always start in stabilize and then switch to position hold. But when the arming check is on ‘all’, how comes it doesn’t check for ‘all’ if it’s in stabilze? That doesn’t sound logical to me.

Also, I’m nearly 100% sure that in the past I could not arm my copter without GPS fix, even when in stabilize.

Is there an option to truely put the ‘prearm check’ to ‘all’, so that it checks everything not depending on the current flight mode? I’d rather not want to start, get to altitude and then be surprised with a non-working position hold modus…

We cannot do what you propose otherwise nobody would be able to arm … as all would mean : with rangefinder, opticalflow, beacons, etc…

In manual mode you are able to arm without waiting GPS as you don’t need it


Set a geofence, then it wont arm without a suitable GPS fix.


Okay, thank you for the replies.
In this case I will set a geofence (I had set one before, I guess that’s why I wasn’t able to arm without gps fix back then).

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MATEK 405 WING does not boot with this new firmware.
I tracked it down to I2C compass connection. If connected copter will not boot. If disconnected it boots fine, but obviously compass is not active.

3.6.4 works fine.

My compass/gps combo is Beitian BN 880p5.param (13.0 KB)

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I’ve pixhawk 2.4.8.will it perfectly work with new stable version.
I’m newbie,kindly help me.

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As a new user you should wait until others have tested this version.

Thank you very much for your suggestion.kindly suggest me another stable version,which could be perform a stable flight for my Hexa…

I’ll grateful to you always… please send me other stable version link and PID tuning also.

3.6 has been out for a while and fully tested. The PID tuning is unique to every airframe.


Thanks for the report about the Matek405Wing not working with the Beitian BN GPS/compass which seems to have an HMC5883L compass on it. I’ve tested with an MRobotics GPS/Compass which also uses the HMC5884L and it worked OK so I’m a little unsure of what the issue could be but we will try and see if we can figure out what’s going on.

I wonder if you could try loading an earlier version of Copter-3.6 onto the board (I see MP has Copter-3.6.2 available in the list of previous firmwares) and then tell me the COMPASS_DEV_ID parameter value (or provide the full parameter list or a log file when running copter-3.6.2)


As @mike says, tuning is unique to each vehicle. We have some wiki pages which give advice on how to tune.

@rmackay9, i restored back to 3.6.4 by compiling based on copter 3.6.4 tag from github. log attached.
compass dev id is 0.
let me also run the copter under 364 - log attached.
BTW - copter booted fine under the battery power after downgrading back to 3.6.4

BTW2 - based on the log (not params) COMPASS_DEV_ID, 466441

p6-364.param (13.0 KB)00000006.log (326.2 KB)

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Good morning.
I did find few different opinions about DO_CHANGE_SPEED command in a mission.

  • Is WPNAV_SPEED overridden by the DO_CHANGE_SPEED command?
  • In mission planner, which columns should I use: first, second or both?!

Thank you in advance.