How to redirect Android kernel output via usb to PC?

[repu1sion]

My Android system with a 4.4.2 kernel fails to boot into a stable state where adb could be used.
Could I redirect somehow a kernel output to get it via minicom and usb?
For example, now in kernel command line I have: "console=ttymxc0,115200"
But no any device /dev/tttymxc0 is created on my PC even so usb cable is connected.
Would it work if I change it to /dev/ttyUSB0 or what should I do to see kernel output immediately?
Thanks.

[nevmair]

On the wandboard there is a DB9 connector, the kernel output is sent there.

You need to connect a serial port
configured to 115200 Baud, 8N1 (8Bits, No parity , 1 stop bit)

The /dev/ttymxc0 device is on the wandboard not your PC.