And again after two days the mirror did what he wants . I was nearly at that Point to throw all away and start fom beginning. Baut then i tried a thing , I disabled Bluetooth AND WLAN. And did it that way:
//sudo nano /etc/modprobe.d/raspi-blacklist.conf
blacklist brcmfmac
blacklist brcmutil
blacklist cfg80211
blacklist rfkill
blacklist btbcm
blacklist hci_uart
And after that a Reboot and
//sudo systemctl disable hciuart
and another reboot .
This works, I hope longer then 2 Days ;)
Now I have to work with the Ethernetport and gonna try it with an USB Wlan Dongle