Cant't select Frame-Type for Hexa

I’m using an APM 2.5 for a Hexacopter.
During the initial Setup, after the Firmware-Download, in the Frame-Type Selection Screen, the only selectable option is Y6B. (This Problem happens with APM-Planner and Mission-Planner) But Mission-Planner complains, that my Board is outdated before flashing the Firmware.
What could be the Problem? I need to configure it as a ‘X’.

Was caused by a misconfigured Telemetry-Radio.