Enabling Login on a Serial Port
To enable login on a serial port other than the default one, add this line to the /etc/inittab file:
T0:12345:respawn:/sbin/agetty -L /dev/ttyS1 115200 vt100
where ttyS1 is the port, and 115200 is the baud rate. You can either edit this file on the target, or on the host as:
<rfs_dir>/etc/inittab