Setting static uart port

[mahesh]

Hallo Experts,
I have connected two serial port to Jetson Nano board(Ubuntu based system). Initially i set
Serial device A to port0 = /dev/ttyUSB0 and Serial device B to port1 = /dev/ttyUSB1;
After shutdown and switch on again, port assigned are changed. How to assign fixed port id to device A and device B


Jaganathan