http://www.linux-usb.org/usbnet/
the simplest possible likely solution might for example be:
modprobe usbnet
FATAL: Module usbnet not found
modprobe dm9601
FATAL: Module dm9601 not found
davicom dm9601 is cheap, popular and in my toolbox...
A few Kindle Fire developers would like ethernet too:
http://forum.xda-developers.com/show....php?t=1813342
selection of reasons provided...
willing to trial if anyone has ideas...