First
The PIN code request for restarting the phone is only working for one card. The second card has to be reactivated awkwardly every time by hand.
Second
Making calls via Bluetooth is not possible anymore because the phone blocks the call with a display request, asking which Sim to use for it.
Third
While writing SMS in landscape modus in the right upper corner a Send button is shown, but if you activate it, the Sms will not be sent but blocked.
For those reasons, I have now re-installed 4.3 again.
