[Namerp]

Since then my Digital Devices Cine C/C2/T/T2 V7 is not recognized anylonger.

Even this is not even close an RPi question

The problem is that Digital Devices didn't provide kernel patches or in kernel drivers for Linux. They provide drivers of course but these kind of drivers delegates DDs work to the distribution providers to include them. So for LibreELEC/OpenELEC you have to create an patch against the kernel source code to get them supported (for each kernel version you have do this again). Don't get me wrong, this is possible but nobody wants to do Digital Devices work (this is no 2min task). Even DVBSky (a cheap china retailer) was able to get their dvb drivers in the kernel -> proper support. If budget manufacturers are able to provide proper drivers you can ask yourself why there isn't any support from DDs side.

There are LibreELEC images with additional dvb drivers (see my sig) but currently only for 7.0 (till there is some official 8.0 alpha/beta) - but even there the dddvb drivers are work in progress because they won't work probably (I have no hw - so I have to wait till someone test the builds).