I installed Cyanogenmod successfully. Unfortunately the camera terminates right after I start it. My guess is, it has something to do with the SD-card. A different Camera app from the PlayStore shows an image at least but prompts me to insert an external storage (sd card) before it can take a picture.
Actually there is a new sd-card with 16 GB inserted. I can access and browse it in the file manager and in Settings -> Storage the sd-cards size is recognized an I can mount/unmount and erase it.
Changing from Android 4.1.2 I did this way:
rootet like this, installed this custom recovery and then installed Cyanogenmod by Macclaw following this tutorial + GAppsMicro.
Due to my problems I wiped everything again and installed Cyanogenmod 11 by TeamCanjica. But same problems there.