hello Andrey1984,
there’re 3 UARTs available on Xavier NX,
UART0 to M2
UART1 to 40PIN
UART2 to debug
please also access Jetson Xavier NX Product Design Guide and check [11.3 UART] for more details.
please also refer to Topic 180166, it is not suggest to change UART2 (i.e. Debug UART) to general UART, because it’s reserve for kernel debug purpose.
thanks