Copter V4.1.1 rc1-bds, I noticed that the secondary IMU (MPU6000) is not recognized. I then noticed that EK3_IMU_MASK was set to 1. I reset to 3 rebooted and this did not persist and still no IMU1. But when I load 4.0.7 they both are recognized again. This issue is also seen on Stable V4.1.0.
@andyp1per I know you have a Slim version of this what do you think?
I have a Matek H743-Mini - I just loaded 4.1.1rc1 on it and got both IMUs. Set FORMAT_VERSION to 0 - all good. EK3_IMU_MASK was 3. Only thing to watch is that the fast sampling mask is set to 1 by default.
I have seen issues when FRAME_CLASS is not set or poor power on 5V etc.
Huh. Would you mind taking a look at the parameter file? Perhaps it’s another Parameter set causing it. This craft flies as is BTW it’s not a new build. I was just going to prioritize the IMU6000 and ran into this in the process.
Matek H743-mini.param (18.3 KB)
Looks correct. Maybe the same issue that someone found on the Lumenier board? Might be worth resetting everything and seeing if its then there.
That did the trick. All back to default accept the correct FRAME_CLASS and TYPE and they are both there. I’ll set everything back and get back to it! Thank you.
Hello,
I reported the same thing in rover 4.1.1-rc1.
For rover I set FRAME_CLASS=1 (Rover) and FRAME_TYPE=0 (undefined; other TYPE are for Omi-configuration which I do not have).
Back to rover 4.1.0, IMU1 is detected again.
After starting back at default and re-configuring/calibrating it’s back to working well. But, I copied pretty much the same parameter values back in so I’m not sure what caused the problem in the 1st place. The only difference is I have not re-done the IMU Tcal routine yet so those are all at 0.
The problem is that INS_ENABLE_MASK is set to 3. That means that only the first two IMUs in the list of IMUs to probe are looked at. In 4.1 there are 3 IMUs that are probed, as some of the MatekH743 boards have an ICM42605, which is the 2nd IMU in the probe list.
So you need to change INS_ENABLE_MASK to at least 7, or you could just set it to the default which is 127, which means “probe all the IMUs in the list”
Ah, I see now. It’s not the number of IMU’s present, it’s the IMU’s available in the board family covered by the same firmware target.
Or IOW, “just leave it at default dude” 
Isn’t this a regression because of the addition of icm42605 ?
INS_ENABLE_MASK = 7 works also for rover on a Matek H743-Mini.