HCSR04 not working

I have a Mateksys f405-vtol (f405-te firmware) with a servo gimbal added to the build via the custom firmware builder. I can’t get the Ardupilot to query the device, which I have verified with an Oscilloscope. I have set servo4-servo8_function to GPIO, which covers all GPIO pins in Group 3 according to the datasheet. I am using servo 5 and 6 for trigger and echo, which correspond to GPIO 54 and 55. 5V and ground have been verified with the scope to ensure good power. I have also checked that the rngfnd1_max is 1 and rngfnd1_min is .1. Rngfnd1_type is HC-SR04. I’m really at a loss for why this isn’t working. I have tested the devices on an Arduino Uno.

Any ideas?

Can you please post a log file with log_disarmed set to 1?

Here are some logs.

log_0_UnknownDate.bin (472 KB)

log_1_UnknownDate.bin (484.0 KB)

tlogs

2025-11-19 07-43-53.tlog (360.9 KB)