Finally I managed to upload the 1.2 Image. If used with a raspberry pi 3 it automatically generates a wifi hotspot which can be used to control it. This is the last 1.x Version. My efforts will be now focused on implementing an algorithm which automatically detects radio signals and save them to a database. Also Version 2.0 will include an update button, which automatically downloads (of connected to the internet) the latest stable version.
https://radio-tracking.eu/project/downloads