Yup, what chipf0rk said. This is slightly out of general scope of the forum, and such a potentially vast and complex subject that it's kinda hard to jot down in a few lines without making it actually more dangerous (dumb analogy ahead: it'd potentially be like giving small children a bunch of sharp objects while only telling them that they could use them to fix their toys [not that I'm calling anyone a child, I just got up, that sounded like a fun analogy... anyyyywaaay
]). [This is also roughly one of the reason you don't see much about USBNetwork from me, even in the very posts it's offered. I figure if you need it, you know how to use it
].
And on our side, for the most basic setup of USBNet, it's as simple as install > click > plug > setup network, so, nothing much to say besides what's in the doc ;p.
Now, hopefully, the worst that can happen is you ending up on the "Your Kindle Needs Repair" screen after a reboot, and, if it is indeed because of an interaction with the Fonts hack, following either what was done in the first few posts of this thread, or at worst, doing a semi-hard
factory reset will get you back in business. It's just much easier/faster to recover from on the spot via SSH, that's all.