Holybro Pixhawk 6X SBUS input broken?


I’m trying to connect a Holybro Pixhawk 6X to a SBUS receiver.

Firmware: Arduplane 4.5.1
Params: Using the factory default
Autopilot: Holybro 6X with Mini Baseboard
Behavior: no RC channel data reported in Mission Planner or QGC

I’ve tried with three different SBUs receivers (Frsky S6R, Frsky X4r, TBS Crossfire Nano), one of which is working on another vehicle with a different autopilot.

Have I misread the wiring diagrams for the 6X, are they wrong, or is there an issue with my baseboard, or am I missing a parameter?

I’ve checked with a logic analyzer - there is data output from the receivers that’s not PWM.

Im using the Holybro fmuv6x, the Ibus input works but the sbus does not. try using ibus if you can.