The problem of the exposing busy, can not abort has been solved. Now however it starts to take a 10 second picture, followed by superfast pictures. Those are now succesfully downloaded, but not of much use. At some point the focus module says it's complete, when I restart the autofocus it starts with a normal 10 sec photo again and the sequence continues with superfast ones (INDI thinks it's still exposing while I can hear the shutter close fast). I'll add a log later...
Makes me think I might have to ditch DSLR's at some point too.
Mm well, tried to have a look at the GitHub source but can't really see a reason why this would be the case either. I have to switch to Windows again for the time being, ver rare clear sky period this week overhere so don't want to miss that.