Copter-4.2.2-rc1 available for beta testing

Copter-4.2.2-rc1 has been released for beta testing and can be downloaded using MP or QGC’s beta firmwares links or it can be directly downloaded from

Changes vs 4.2.1 are in the ReleaseNotes and copied below:

  1. MambaH743v4 and MambaF405 MK4 autopilot support
  2. Second full harmonic notches available (see INS_HNTC2_ parameters)
  3. UAVCAN memory usage reduced (see CAN_Dn_UC_POOL parameter to control DroneCAN pool size)
  4. VTOL QuikTune lua script added
  5. Watchdog (caused by hardfault) saves crash dump logs to SD card
  6. Bug fixes
    a) Circle mode stops below altitude fence
    b) CRSF protection against watchdog on bad frames
    c) CRSF reset in flight handled
    d) FFT init watchdog fix when ARMING_REQUIRE=0 (not actually possible on Copter)
    e) OSD flight modes menu includes newer flight modes
    f) Param download (via MAVFTP) fixed for params with overlapping names
    g) PWM rangefinder bug fix and added SCALING parameter support
    h) Replay bug fix when EK3_SRCs changed
    i) SERIALx_OPTION fix when “Don’t forward mavlink to/from” selected (resolves MAVLink gimbal detection)
    j) TradHeli Autotune fix which could cause incorrect gains to be loaded
    k) VL53L1X rangefinder preserves addresses

Any and all feedback is greatly appreciated! If all goes well we will release this as the official version in about a week.


How it will handle this script memory issue with all board’s when its comes within firmware as point no 4 you mentioned @rmackay9


If you’re using CAN then it is possible this version will help with the memory issues you’ve found. Txs for giving it a try!

You are saying about CAN …what does mean here using CAN ?



The CAN ports can be used for various sensors, GPS, optical flow, compass, ESCs… if any of those are used then you’ll find this new beta uses a bit less memory.

Im using CAN gps only …then let try with this version thank you @rmackay9

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@rmackay9 i have loaded AC 4.2.2 rc1 on CUAV V5 Nano and used CAN gps only on CAN1 port but still Prearm : Script Out of memory.


If you can provide a log file we may be able to give some advice. So far I don’t think we have a bug though, it’s just a limitation on the amount of memory available on the autopilot vs the amount of memory required for all the enabled features.

here is the on board log.

@rmackay9 did you had look at log to find reason for lag of memory?