Browserhax is "blocked" through DNS. If you disconnect from internet, suddenly the nag disappears and you can use the browser again. So this nag is really, really thin. The way to do it is:
1. setup browserhax in your PC or laptop with the yellows8's sources of browserhax at github with a web server with php like XAMPP.
2. launch your phone's (android) wifi acces point but make sure your phone can't access internet (disable data).
3. configure the 3ds and the pc to connect to your phone.
4. find what is your pc IP address inside this new network and start XAMPP.
5. visit browserhax using this link
http://XXX.XXX.XXX.XXX/YYY/3dsbrowserhax_auto.php (where xxx is the pc's ip address and yyy is the route you laid the files in xampp
6. ???
7. profit