How to get serial port connection to Neo Freerunner?

[Dave Schmidt]

Hello everyone,

I have my Freerunner connected to the PC via USB cable. SSH terminal is open.

I want to access the phone via serial interface (to flash osmocombb firmware).
Could/should the same usb cable be used for that? I have 
created a node (mknod /dev/ttyUSB0 c 188 0) and inserted module
(modprobe usbserial) on the PC, but usbserial does not find any device.
The report is only:

usbcore: registered new interface driver usbserial
USB Serial support registered for generic
usbcore: registered new interface driver usbserial_generic
usbserial: USB Serial Driver core

What am I missing?

Thanks a lot,

D.