After upgrading to 6.0 there is NO bootloader menu.
After holding the volume down button and the power button simultaneously there is only the message “Kein Befehl” (in german) and and an android robot.
Looks like you’ve entered the ADB command shell, in which you can see your device from your computer. It waits for adb commands entered there.
Do you want to get into recovery?
That works a little differently with Android 6.
Yes were ist the recovery menu? Is there none?
Just tap the link and you’ll know.