It looked like the software upgrade could not complete. After 30 minutes it was still not finished and showed the same message "software upgrading please wait..." if you look carefull.
So I reset the player and start it up than the software upgrade started again,...
After a reset while seeing "loading" message on the screen I held ">>" button and a formatting procedure started, before the software upgrade could start again. That removed the files from disk and a factory (chinese) version was on the player again.