Pixhawk 2.1 randomly reset parameters

Hi everyone,
I’m operating a Nimbus VTOL plane and she flies great running 3.9.8 firmware. But 2 weeks ago, when I plugged the battery, suddenly all parameters in the Pixhawk were reset to default parameters of an ArduPlane (not VTOL Plane). I thought this might be a bug of the firmware, so I updated to 4.0.1 and reload the parameters of the Nimbus. Everything seemed to be back to normal, I flied another 5,6 times without problems. However, today it happened two times in one afternoon. Every parameters were reset to default ArduPlane.
Could anyone have any idea about this problem? this is a firmware problem or a hardware problem? thank you so much.
Best regards,

That’s interesting. I had the same thing happen to me on an octocopter using a black cube a few weeks ago. I’ve never seen that happen in years of using Ardupilot and I didn’t figure out the cause.

Can you guys open an issue in GitHub, with as much detail as possible: firmware versions, hardware, gcs used etc. thanks

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This week, it happened like every day. We did 6,7 mapping missions per day and I have to reload the parameters one or two times each day. Really confused!

Will do. Fortunately, Tridge was actually connected remotely to the copter at the time and he was the one who discovered the parameters had reset to defaults. I think he even has logs of the flights from that day.

I’ve had a bit of a discussion about this.
In short, when parameters fail to be read from memory, the memory is wiped.
Why the parameters are failing to be read I can’t guess, for a particular case.
Please raise the issue in GitHub: there may be a better way to handle the read failures, but if the issue isn’t in GitHub it will probably not be looked at.

I guess this is related to https://github.com/ArduPilot/ardupilot/pull/13119 ?

I don’t use GIT but I’ve opened an account and I’ll put this in the issues now. Hopefully it will end up in the right place.

@lakhe85 Can you please give more details?

What code version? What parameters set? What accessories fitted etc…

Do you still have the vehicle?

Is it still repeatable?

We have now three reports that I can see, 2 cube’s, 1 Pixhawk 1.

It’s obviously possible it could be a hardware problem or a software issue, but either way, a repeatable setup is needed to troubleshoot this

The GitHub issue is probably the best place for this discussion

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This is a VTOL nimbus that our company purchased from Foxtech (https://www.foxtechfpv.com/foxtech-nimbus-vtol-v2.html), A RTK grey combo with Pixhawk 2.1 Standard Set with Here GNSS, firstly ran the 3.9.8 arduplane firmware.
Here is the flight history of the plane:
She had a crash in her third long-time flight due to battery running out (we had made some flight tests before using her for long-time missions), had some damage in the main fuselage, broke an airspeed sensor (not the tube but the sensor circuit inside fuselage) and an ubec for mapping camera. We fixed everything, she was back to work like a charm and flied another 10 long-time missions (20-40 km total distance per mission) during 2 months before the parameters reset problem happened the first time.
I decided to update the firmware to 4.0.1 and reload the parameters (we did not change the parameters much from defaults of Foxtech, only the failsafe time and landing altitude that I could remember. This is the parameter file: https://1drv.ms/u/s!AjRNNKW2S9ZBlZAqR3ReA5m2aLpsFQ?e=GVlrCq)
She continued flying normally another 12 missions in 2 days (about 25 km total distance per mission) before it happened again. I helped the operation team to reload the parameters, and she flied great for another 10 missions before coming back to company for regular checking and maintenance. That time, I started this discussion to find out the problem.
Last week, she was out again for business. However, this time the problem happened like one or two time everyday during 4 days (we flied about 6~7 missions per day). The parameter reset just stopped for no reason two days ago when she flied 8 missions without any problem. I don’t know if the flight control reset problem might be a hardware problem due to her first crash or not.
She is actually coming back to me now for maintenance and I will do additional checks on the plane if you guys need.
Best regards,
P/S: the Foxtech nimbus VTOL use a Dual Battery Swapping Board called PG20 for using LiPo and Li-ion batteries simultaneously to maximize flight distance (https://www.foxtechfpv.com/pg20-dual-battery-swapping-board.html). However, we normally plug only one Li-Po battery because we only fly short range (up to 25 km).

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This is strange.

As a start, I always err on the side of caution, swap out the cube. It’s not worth crashing if that fixes it. But if the problem continues with the new cube, then we confirm it’s not from the crash.

I would be happy to RMA that cube, I assume you got it via foxtech? I would like to get to the bottom of the issue


We are pretty sure that we have found the solution to this issue and it will be included in Copter-4.0.4 and Plane-4.0.6. So as not to spam here there and everywhere the discussion is over on this thread.