I only wanted the DVB-C-Part of my stick (dvb_usb_rtl28xxu), but after VDR access the first frontend of this device (/dev/dvb/adapter0/frontend0), the device won’t be accessible on its other frontend (/dev/dvb/adapter0/frontend1), so I had to find a way to disable the first frontend.

If you have trouble scanning any channels, please take a look at you dmesg whether there was a problem loading the correct firmware. For me it looked like this:

user@host:~# dmesg | grep firmware
[23945257.415086] mn88473 7-0018: Direct firmware load for dvb-demod-mn88473-01.fw failed with error -2

Your firmware is most certainly somewhere in the github directory of OpenELEC: https://github.com/OpenELEC/dvb-firmware/tree/master/firmware

For example, I had to copy the dvb-demod-mn88473-01.fw to /lib/firmware/:

sudo wget https://github.com/OpenELEC/dvb-firmware/raw/master/firmware/dvb-demod-mn88473-01.fw -O /lib/firmware/dvb-demod-mn88473-01.fw

Check whether w_scan works:

sudo w_scan -fc -c DE >>dvb-c-channels.conf

Search for the DEVPATH of the frontend which you want to disable (for me it was adapter0/frontend0):

user@host:~# udevadm info --query=all --name=/dev/dvb/adapter0/frontend0 | grep DEVPATH
E: DEVPATH=/devices/pci0000:00/0000:00:14.0/usb3/3-4/dvb/dvb0.frontend0

Then add a new udev-rule as a new file /etc/udev/rules.d/11-disable-frontend0.rules:

ACTION=="add", SUBSYSTEM=="dvb", ENV{DVB_DEVICE_TYPE}=="frontend", DEVPATH=="/devices/pci0000:00/0000:00:14.0/usb3/3-4/dvb/dvb0.frontend0", ENV{dynamite_attach}="no"

I must admit that this didn’t work for me. I had to move the frontend0 manually to a higher number, disabling it by this for vdr:

user@host:~# mv /dev/dvb/adapter0/frontend0 /dev/dvb/adapter0/frontend9