On Thursday 09 June 2016 15:44:03 Harms, Hannes wrote: [...]
But unfortunately now batctl always says that the mesh is not activated (no interface), which is obviously wrong. Maybe I made somewhere a mistake while porting the code.
Can you guess what goes wrong?
I don't even know what code you've ported. Was it batman-adv 2016.2? Maybe you are using an really old version and ran in an already fixed bug  which made it impossible to add down interfaces and later use them in B.A.T.M.A.N. V. Or there is something else because there is no "mesh is not activated" or "no interface" error in batctl/batman-adv and so I have to guess what you may have meant and what you have tried to execute.
Kind regards, Sven