I flashed again! It's NOT the SIM Card setting. I think there is an app or a patch which breaks it. I will leave it now for a while with no apps installed and do some reboots. ANd watch.

The SIM Card by the way is only getting lost after reboots. Not while Sailfish is running.

@mosen and @Kabouik can you make a list what apps and what patches you have installed. That would help me to find the culprit.

I'm quite sure there is no hardware problem! EVERY time I flash SIM is recognized again without any problems! I never ad problems on Android and at the beginning with not much installed.

You know, that I didn't waited to long with flashing, so the device had no problems with the SIM Card under Sailfish for quite a long time. It always started, when I started to install a lot of stuff.