I'm having trouble getting this to work on my 10.1 n3DS. I turned off wifi, typed in http://yls8.mtheall.com/browserhax_fright.php to the browser. Then I exited the browser, turned on wi-fi, rebooted console and opened the browser right away. I still get the update message pretty much immediately.
Do I need to mess with my DNS or anything?
Yes you need to change your DNS.