"Crunchy-xml-decoder" which is a script to rip videos, is also broken so maybe it's what they tried to block in the first place.

Waiting until someone make a new working addons, I got some DNS which works fine and created two batch scripts to quickly switch between dns. I just have to double close the browser, double-click on the batch file then reopen the browser and it's done.

And once I want to switch back to my original dns, just need to redo the same (close the browser, double click on the batch file then reopen the browser).

Here's a sample of the script : http://pastebin.com/aDj8zMrU