What does "gyros not healthy" mean

I switched back to copter FW 4.0.7-stable from the more recent 4.1-dev and 4.1.0-beta, and now I am seeing the following in the HUD and message panel:

6/8/2021 9:26:12 PM : PreArm: Gyros not healthy

What does “gyros not healthy” mean, and how can I fix it? The gyros are built into the FC (Matek H743-slim), so I am at a loss as to what is going on.


This must be the same as the “internal error 0x1000000 L168 imu_reset” error that I was seeing in FW version 4.1.0… there’s a bug in arducopter around how Matek’s H743-slim’s inertial sensors are initialized and/or read. @rmackay9, I mentioned this in another thread, just fyi. The earlier version 4.0.7 seems to have the same bug, but it manifests differently in MP. This also may be the reason why the “Calibrate Level” operation under “Setup -> Mandatory Hardware” fails on this board with an error that states “Command Failed to Execute”. Perhaps the bug is that the IMU is not fully supported on this board, so the accelerometer and gyro aren’t properly getting initialized.

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This is what the wiki says:

Gyros not healthy : one of the gyroscopes is reporting it is unhealthy which is likely a hardware issue. This can also occur immediately after a firmware update before the board has been restarted.

Maybe you just didn’t restart the board after updating?

Thank you @Yaros. I did restart the board. So I guess it’s likely a hardware issue then…

Your hardware is deadware. Get a Pixhawk or a Cube.

@OldGazer, you are referring to two $250 devices, vs. an entirely comparable FC that currently sells for $70. For the quick-and-dirty research project I am currently working on, spending $250 for an FC seems like craziness. :wink:
So before I go that route and spend a great deal of money, I would respectfully like to explore all available options to make this supposedly supported hardware work as described. Makes sense?

H743-Mini is working well for me so sure why not.

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The Matek H743-slim board has two IMUs (MPU6000 (SPI1) & ICM20602 (SPI4)). Looks like if I disable the first one (MPU6000) and have only the second one enabled (ICM20602), all pre-arm checks succeed, all errors disappear, the level calibration finally succeeds, and I can finally arm the quad. So… progress!

Now the remaining mystery for me is why the MPU6000 IMU is causing all these issues, and I am guessing it’s either because it’s damaged (not sure how, it’s a new board), or the Ardupilot driver support for it is buggy. If the talented dev team needs my help in exploring any potential fixes for this IMU (@rmackay9, @andyp1per, etc), please do let me know and I would be happy to beta-test. :smiley:

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The Mini has the same IMU suite. Not seeing the errors . Always running the latest Dev version.

Typical boot, ready to fly:


Thanks again for the follow-up and good idea to disable the first IMU. I’ll pass this onto Matek as well.

I think the evidence is clearly pointing towards a hardware issue. My personal guess is they’ve got a manufacturing issue with this particular type of board.

EDIT: one of the developers has the same type of board that is suffering from one of the IMUs failing. It would be nice if it was a software problem because then we could fix it but I’m afraid it is hardware.

You are talking about the Cube. I’m talking about a Pixhawk 2.4.8 https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=Pixhawk+2.4.8&_sacat=0

You can go bare bones or full tilt boogie for under $200.00.


We have the same issue with one our Cube.
The sequence is almost always the same. After the initial boot up of the drone, we cannot arm be cause of Gyro not healthy. Then if we reset the gyro it works and we can fly the all day without any further error message. The next day we’ll have the same problem.

Any idea?


good afternoon the same problem cuav x7, prearm gyros not healthy, maybe there are some solutions firmware version 4.0.7 return to later ones does not help

I have similar issue with Arducopter 4.1.5 and an #hardware-vendors:mrobotics #mro-control-zero-h7.

It shows up sporadically but disappears almost immediately again without reboot etc.