2. Hack is fully to remove over exlink only
3. Downgrading firmware does not remove hack.
4. It is not safe. It is written on wiki

I removed this image, to don't distribute potentially dangerous method. But you can follow another manual, where is no danger to brick the TV. But here is only run.sh executed. No web interface and other stuff.
http://forum.samygo.tv/viewtopic.php?t=1076#p9261