I have a strange problem that I have never seen before 
When I set SERVO_BLH_MASK: 20 Which Sets Servo 3 and Servo 5 output to DSHOT 300
THEN repower the flight controller
Channels # 4 and # 6 stop working … See attached picture of the servo output, it shows zero signal. But, in the radio calibration page, the channels work correctly.
Matek H743
Latest Ardupilot version 10 Jan 2024
Is this a bug ???
No. It’s Timer Groups.
Matek H743
All motor/servo outputs are Dshot and PWM capable. However, mixing Dshot and normal PWM operation for outputs is restricted into groups, ie. enabling Dshot for an output in a group requires that ALL outputs in that group be configured and used as Dshot, rather than PWM outputs. The output groups that must be the same (PWM rate or Dshot, when configured as a normal servo/motor output) are: 1/2, 3/4/5/6, 7/8/9/10, 11/12, and 13 (LED).
Hi Dkemxr,
THANK you for the fast answer !!! This makes it an easy fix 