The TX2/TX1 by default will output the serial debug terminal to /dev/ttyS0. As such, if this UART port is required by an application or external hardware it can be disabled. In most cases /dev/ttyS0 is assigned to UART0 on Connect Tech’s carrier boards. For additional information about the UART interface on the TX1 carriers please refer to the following KDB:
When operating the TX2/TX1 proceed as root in the terminal, and locate the ttys0.conf file in /etc/init/. When this file is found, copy it to another directory as it may be needed later if debug terminal is desired. Now remove the ttyS0.conf file from /etc/init/ and reboot, UART0 ttyS0 should now be freed from the debug serial output.