Why GPIO 17 and 18 available for UART works my signal steps

I am on navio2 with raspberry pi 4B and I configured my gps 2 on Uart0 GPIO 14 and 15, I want to use the two pin spare GPIO 17 and 18 as indicated on the config, but I have problems ex: I changed in config.txt the option: dtoverlay=disable-bt, enable_uart=1, dtoverlay=uart1,my I want to use it for telemetry with my circuit Arduino nano every no output signal on my oscilloscope of my config in Arducopter settings is good I programmed serial 2 a 57600 and mavlink 1 then the configuration file in emildtool Arducopter (telem1 for console, telem2 for gps2 -E /dev/ttyAMA0, telem3 for telemetry -D /dev/ttyS0,

Hi @Jack1383,

Your scenario is not yet clear to me, could you please elaborate on it a bit further? Please specify what actions you performed step-by-step and how you configured the additional hardware.