Copter-4.1.2 released!

Copter-4.1.2 has been released as the stable version and can be downloaded using MP or QGC or downloaded directly from

The changes vs 4.1.1 are in the release notes and copied below

Changes from 4.1.1

  1. CAN_Dn_UC_OPTION param added to help resolve DroneCAN DNA conflicts
  2. Durandal with alternative ICM-20602 IMU
  3. OBAL autopilot support (Open Board Architecture for Linux)
  4. FETtec One ESC protocol support
  5. Bug Fixes
    a) ADSB vertical velocity reporting fix
    b) APM/LOGS directory creation fixed on some boards
    c) AutoTune fix to disable SMAX limits that could interfere with tune
    d) EKF3 fix to switch to non-zero primary core when disarmed
    e) Notch filter update rate fix
    f) Surface tracking fix if rangefinder glitches
    g) TradHeli rename of H_COLL_HOVER to H_COL_HOVER

We didn’t get a lot of feedback on the 4.1.2-rc1 beta release but hopefully this is because nobody found any problems and Plane users have already been flying most of this code for a couple of weeks. Still, please tell us if you see any issues.


Can you please describe more f) ?

Hi @Vaclav_Demeter,

Here’s a link to the PR that fixed 5f and it includes some screen shots showing how when the rangefinder glitched the target altitude was reset to the current altitude above the surface.

So for example if the vehicle was climbing up a hill at a target of 3m over the surface, it is likely that the vehicle would fly at exactly 3m above the surface, it might instead fly at 2.5m. If the lidar glitched then the target altitude would be reset to 2.5m above the surface and the vehicle might drop even lower to 2m above the surface. So every time the lidar glitched the vehicle might “permanently” gain or lose some altitude above the target.

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Thank you Randy and all the dev team at Ardupilot and the helpful people that answer my questions

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