After Upgrading to 4.3 stable, I get: "Prearm: Mount not healthy"

I upgraded my firmware on my board, and now I get a new prearm message that:

“Pre-arm: Mount not healthy”

This doesn’t seem right. The last time I tried arming it, I didn’t get any warning about a mount not being healthy, and haven’t flown it.

Need more info, like the flight controller, the Mount details and so on.
Ideally set LOG_DISARMED,1 and reproduce the error then set LOG_DISARMED,0
Let’s see that .bin log.

If you’ve got a Pixhawk1-1M or similar there are some features disabled in the newer firmware versions, you can use the custom firmware builder to add in required features - if that is the issue.

I’m using an orange cube on an octocopter. I’m not sure what you mean by “mount details” though… Here’s my log file:

Problem still exists (thought I had it solved briefly) I tried loading the old firmware version, and did not get the prearm warning.

An example of a mount is a gimbal, do you have any such gear mounted?

No; I don’t think so. I do have landing gear connected. I tested it, and it’s working fine. At one time I was also trying to get my gimbal working on it (without siccess,) so it’s possible I’ve adjusted something in the past with a gimbal. Do you have suggestions of paramaters I should check?

Here’s a look at my “Camera Gimbal” settings. Notice that for “type” there are no options

I haven’t looked at the mount parameters.

We’ll probably have to wait until Xfacta answers, he might have used the mount feature before

params2022november23.param (18.2 KB)

I uploaded my params, in case it’s useful.

Change MNT1_TYPE,6 (Gremsy) to MNT1_TYPE,0 (none) or something else like 1 (servo) if you are going to set it up.

You should be able to stay with the latest stable firmware


This is a slightly old thread now but just to explain what happened, in 4.3 we improved the gimbal drivers a lot including adding health reporting. Because MNT1_TYPE was set to a non-zero number AP was expecting a gimbal and when it couldn’t find it, it threw up the arming error.


This was how to satisfy the warning, so it’s clear:

Thanks for clarifying. I’m sure anyone else experiencing a mount that they had partially setup in the old firmware will appreciate it as much as I do.



So the cube will not arm when a gremsy gimbal (6) is not connected?

The cube will not arm when a gimbal is configured, but not connected.

If you do not have a gimbal connected, do not enable the gimbal.

ok for a normal user this is a problem. Especially when they have different payloads. Can this taken of the not arming warning?


The ARMING_CHECKS parameter controls which arming checks are run so if you check all the other boxes (except all) and then uncheck “Camera” it will not run the check.


perfect thanks for the info

Good day,

I have the same issue. Ardupilot Copter 4.3.7 with Gremsy Gimbal T3V3 (tested firmware versions: 7.7.3 preview, 7.7.3 official and 7.8.0 beta) installed as MNT1 and connected to SERIAL2. Followed the manual here. If I set MNT1_TYPE to 6 (Gremsy) I get “Pre-arm: Mount not healthy” message. Setting MNT1_TYPE to 0, 2 or 4 leads to resolving of the problem. However, I need to be able to control my Gremsy Gimbal with MavLink messages from GCS (now I simulate GCS messages with RaspPi 4B connected to Orange Cube COM4 sending MavLink Messages via Serial port to AP using pymavlink and Command with ID 205, in the future RaspPi will transfer data from 5G/LTE/Wifi to Serial but the same messages).

Would appreciate any help to resolve the issue.