@NiLuJe will correct me if I'm wrong but I
think that USBNetworking hack had some files on hidden Kindle memory and you resetting you Kindle to factory setting
probably deleted those files also, so copy of /mnt/us/usbnet folder will not be enough to have fully funtional USBNetwork/ SSH access working.
And you will probably have to repair/debrick your Kindle using
Kubrick.
But better just wait for @NiLuJe to notice this thread, he will confirm my guess (or not), and tell you how you should proceed.
While you're waiting go ahead and connect you Kindle to wall charger to fully charge it's battery.