Hello, Adam and L4 Hackers.
Thanks for answering.

When I run 'ifconfig', nothing have happened.
I guess that the cause is /etc folder in ramdisk is not enough to run 'init'. 

Would you mind if I ask you another question ? 

Must also I modify 'arm-rv.io' ? 
or must I modify 'l4lx_xs.cfg' ? 
or Do not I need do it ? 

If I have to modify them , how to modify  ? 
(I'm using Freescale imx6q SABRE SD board.)

If you give a bit me hints, I'd appreciate.