i hate to say it, but from my research you will def need the internet to downgrade the firmware. The only place ive seen that will let you is the downgrader through homebrew, which they all need an internet connection. I ordered a network adapter for my Wii off of nintendos site for just a lil over $25. But since you have built in Wi-Fi you might wanna try to see if someone may have an open router close to you or something. You could hit off their router long enough to run it all.