Boot USB - No Network Connection

[IriDium]

I can see no reason for the N/W not to work if the process was followed.

It should have nothing to do with the SD card as that is just used for the boot process (I assume you changed cmdline.txt to root=/dev/sdax when using the USB stick).

I'm also assuming it is a model B and not a B+ (Process has not been tested but should work)

If it would not boot again then it's possible cmdline.txt or config.txt were corrupted (Maybe with non windows line feeds or something).

Try again, and if not N/W "exit" via the shutdown menu and sign in xbian/raspberry. Then use xbian-config. System settings -> Network interfaces to set the values.

If still no luck post cmdline.txt, config.txt and dmesg via http://www.pastebin.com