Copter-4.0.4 released!

WARNING: An issue has been found with Copter-4.0.4’s Acro mode. This issue causes the vehicle to be very sluggish to respond to the pilot’s input and could lead to a crash. Please do not use Acro mode with Copter-4.0.4. Other flight modes are not affected. Copter-4.0.5-rc1 will begin beta testing a fix early next week (Oct 5th 2020).

Copter-4.0.4 has been released and should appear in the ground stations as the official version within the next few hours. This is quite a large update from 4.0.3 and the changes are listed in the ReleaseNotes and copied below:

Changes from 4.0.3

  1. Bug Fixes:
    a) I/O CPU fix so safety remains off after inflight reboot (Critical fix)
    b) Acro mode yaw expo supports values under 0.5 (see ACRO_Y_EXPO param)
    c) Auto mode Loiter-Turn commands points towards center
    d) Change-Speed commands applied smoothly
    e) Compass scaling factor threshhold increased
    f) EKF compass variance reporting to GCS made consistent with onboard logs
    g) Gimbal control using RC input ignores RCx_TRIM param
    h) Holybro Durandal buzzer fix
    i) Parameter reset fix caused by Eeprom race condition
    j) Read-only parameter write failure msg only sent once to GCS
    k) Compass declination can be overriden with COMPASS_DEC param (and EKF stops using world magnetic tables)
    l) Terrain database (SRTM) file fix (will cause all terrain to be reloaded after upgrade)
    m) Watchdog monitor memory increased (may have caused watchdog reset)
    n) Hex CubeOrange 2nd current sensor pin correction
    o) Lightware I2C driver fix when out-of-range
    p) MatekF765-Wing voltage and scaling fixed
    q) MatekH743 baro on I2C2 bus
    r) Proximity (360 lidar) ignore zone fix
    s) LIS3MDL compass enabled on all boards
    t) TradHeli servo test fix
    u) Precision landing logging fix
    v) Mavlink commands ignored after reboot request
  2. Bootloader update to reduce chance of param resets during firmware load
  3. Compass ordering and prioritisation improvements
  4. Flight controller support:
    a) CUAV-Nora
    b) CUAV-X7
    c) MatekSys H743
    e) mRo Nexus
    f) R9Pilot
    g) Bitcraze Crazyflie 2.1
    h) CUAV Nora V1.2
    i) Holybro Pix32v5
    j) mRo Pixracer Pro
  5. GPS moving baseline (aka Yaw from GPS) for UBlox F9 GPSs
  6. Graupner Hott telemetry support
  7. Landing detector filter improvement improves detection on hard surfaces
  8. Object Avoidances Fixes and improvements:
    a) BendyRuler runs more slowly to reduce CPU load and reduce timeouts
    b) Dijkstra’s avoidance works with more fence points
    c) Proximity drivers (i.e. 360deg lidar) simplified to reduce CPU load
  9. ProfiLED LEDs support
  10. Smart Battery improvements:
    a) Cycle count added
    b) NeoDesign battery support
    c) SUI battery support
  11. Other enhancements:
    a) Betaflight X frame type support
    b) Landing gear auto deploy/retract configurable using LGR_OPTIONS param
    c) MOT_PWM_MIN/MAX pre-arm check (checks fail if only one has been set)
    d) Solo gimbal and camera control improvements
    e) USB IDs updated to new ArduPilot specific IDs
    f) Benewake RangeFinder parameter descriptions clarified
    g) Pre-arm check of attitude ignores DCM if multiple EKF cores present
    h) Matek H743, 765-Wing and F405-Wing get DPS310 Baro support

If you are using Mission Planner, it is best to upgrade it to the latest stable version using the Help >> Check for Updates button. Once upgraded you’ll see that the Setup >> Mandatory Hardware >> Compass page has been enhanced to include a compass prioritisation table. This allows users to more easily see all the compasses available on the autopilot and select which they would like to use.

Thanks very much to the beta testers who helped us with this large point release!

If you notice any issues please report them below or in a new thread within this Copter-4.0 category.


Cheers, thanks for the contribution of the development team!

1 Like

Point no 11 support xframe type is for all vehicle type like hexa,tricopter& OCTACOPTER also?

Wow, thank you very much to all developers for all of the hard work. This is a significant mile stone for ardupilot community. At the moment I just have simple question regarding point 10, smart battery improvement. How to access this configuration menu? Is it possible to use “smart bms” that available in the market now (Aliexpress) to configure the smart bms in our Mission Planner??? I mean here is, how to get access to the smart battery configuration menu if I use “smart Bms”…

Great work as usual, where can we find some infos about neodesign and sui smart batteries?

This update did not include a dshot Protocol fix for the Kakute F7 controller?

No I don’t think it did. I meant to mention this to @rmackay9 but forgot - sorry

1 Like

Awesome work dev team. Appreciate all teh hard work and dedication.
One question…what in the world is 1. ProfiLED LEDs
Not heard of this before…

a string of addressable LEDs, see a quick/easy/simple demo here:

I expect you’ll be able to have all your copters doing this by lunch time tomorrow :slight_smile:

1 Like

@kalai1219, No, I’m afraid the BetaFlight X frame support is only for quadcopters. Even in master (aka “latest”) it is the same so if you’d like it for other frames mnybe raise an issue in the issues list?


We still haven’t added wiki pages for the Sui and NeoThings batteries from HiTec. The Sui battery driver is from the Hitec Xeno FX plane and won’t be sold separately I hear.


HiTec says they are planning to sell the NeoThings battery at some point but the timeline isn’t clear yet I’m afraid. It is a 6S 9000mAh Li-Ion smart battery



We only have this simple smart battery wiki page which mostly focuses on the Maxell SmartBattery. The BATT_MONITOR parameter is the parameter that needs to be set and there are a few “SMBus” options. Setting BATT_MONITOR = 7 (“SMBus-Maxell”) may work with other smart batteries.


Thanks! Here’s the link to the NeoPixel wiki page.

Thanks Randy
Didn’t know this was neopixel.
Very cool will need to see if I have a use for it.


Thanks Everyone
Loaded 4.04 onto an Matek F405 Wing Flight Controller and all works well. The only issue is the Err BARO-4 and Err Compass-4 that keep repeating in the logs

David Ardis

wrong place to post a new message

Anyone having issues with Dataflash logs not being available.
I can see them if I pull the sd card, but they are not available to download via MP.

1 Like


Yes, I hit the same issue this morning but updating to lastest beta MP resolves the problem. If you’re seeing the issue using stable MP then I’m sure Michael Oborne will release a new stable soon.

Super Randy thanks man.
Will update asap. I suspect something like that should be done.


1 Like