Hi Marcus & Tom,
yes, iam using the buil-gnuradio script. The process was interrupt when the gnuradio build process was working. I had to start cmake manualy like described on the gnuradio website for "native compiling" and it was ok.
I know uninstalled the gr-osmso via make uninstall and the rtl-sdr via make uninstall.
After them i have done a make and make install in rtl-sdr source directory and the librtlsdr was installed.
After them i have done a make and make install in gr-osmo source directory.
I also add the driver to the blacklist.
Now the RTL stick is beeing recognized by gnuradio on the bananapi :-)
Thanks a lot,
Andreas