Hey thanks for your advice. I will try it soon but at first i have to flash my fritzbox one more time because i accidentally erased something in the network config and now its not reachable anymore.
I know and i did not download 'something' from third party site but there was this hint here in the forum and it looks like what its supposed to be.
But even without this vectoring firmware it should at least connect to the DSLAM or not?