Servo 3+ functionality bug

[C17MooseLoad]

Describe the bug

In betaflight I am not able to control any PWM outputs other than those assigned to either servo 1 or servo 2.

To Reproduce

Properly configured 4x motor quad. Additionally properly configured 4x pwm controlled devices connected to pads with the proper timer. Assign resources to servos 1, 2, 3, 4 and assign aux channels to control servo. Resources assigned to servo 1 and 2 respond properly when aux channel manipulated. Re-assign resources, swapping 1, 2 to 3,4 and vice versa and retest to confirm pwm operation. Devices on 1&2 now function properly while the previously functioning 1&2, now on 3&4 servo fail to respond.

Expected behavior

all servos respond to aux channel control when properly connected and configured.

Configurator version

25.12.0-rcc3

Flight controller configuration

this occurs on all FC tested with proper resources.  My focus has been on H743 processor FCs due to increased resources available on these boards

Add any other context about the problem that you think might be relevant here

channel forwarding appears to have no affect on PWM control.

[Erics1337]

Thanks for the report. Your testing confirms this is a Firmware issue rather than a Configurator bug.

Since swapping the resources caused the working pins (assigned to 1&2) to fail when moved to 3&4, and the failing pins to work when moved to 1&2, we know the Configurator is successfully saving the resource mapping. The failure is specific to the Servo Index (3 & 4) on the H743 target, which suggests a timer or DMA allocation issue in the firmware itself.

You can verify the Configurator did its job by checking get servo in the CLI to see that the settings are saved correctly. Please verify this and then open an issue in the betaflight/betaflight repository.

[haslinghuis]

Setup channel forwarding - https://youtu.be/L-6r2iX1p6s and check resource show all in cli