i have managed to get usbnetwork working, i had to rename the file to auto, regular usbnetwork command didnt work.
i can ping yahoo/amazon from cli , however when i try to register it still doesnt work, i have tried running usbnet-enable , Get the following
system: I usbnet-enable:def:enabling USB network tethering...
route: SIOCADDRT: File exists
system: I mntroot:def:Making root filesystem writeable
system: I usbnet-enable:def:tweaking luigi config
system: I mntroot:def:Making root filesystem read-only
system: I usbnet-enable:def:done! restarting the framework...
system: I framework:def:resetting booklet framework
system: I framework:def:stopping booklet framework
system: I start.sh

signal=15,exitval=143:CVM stopped using SIGTERM
/etc/init.d/framework: line 1: cannot create /proc/bd/boot_milestone: nonexistent directory
[root@kindle bin]# start.sh: starting framework
I can still access internet from CLI, Not browser or register.
Its a kindle DX running 3.2.1