[SOLVED] Unable to install libav-tools, ffmpeg etc. on Stretch

[Nachteule]

Yup

Terminal

root@kmxbibr ~ # LC_ALL=C apt-get install -s ffmpeg libavdevice57 libsdl2-2.0-0 libwayland-egl1
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'libwayland-egl1-mesa' instead of 'libwayland-egl1'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libwayland-egl1-mesa : Depends: libegl1-mesa (= 13.0.6-1)
E: Unable to correct problems, you have held broken packages.
root@kmxbibr ~ # dpkg-query -s xbian-package-firmware
Package: xbian-package-firmware
Essential: yes
Status: install ok installed
Priority: optional
Section: firmware
Installed-Size: 16736
Origin: XBian
Maintainer: mkreisl <development@xbian.org>
Architecture: armhf
Version: 6-1494173043
Replaces: raspberrypi-artwork, raspberrypi-bootloader, libraspberrypi0, libraspberrypi-bin, libraspberrypi-dev, xbian-update (<= 1.0-0.4)
Provides: libraspberrypi0, libraspberrypi-dev, libegl1-mesa (= 8.0.0), libegl1-mesa-dev, libegl1-mesa-drivers, libgles2-mesa-dev, libgles2-mesa (= 8.0.0)
Conflicts: libraspberrypi0, raspberrypi-artwork, raspberrypi-bootloader, libraspberrypi0, libraspberrypi-bin, libraspberrypi-dev, xbian-package-firmware-6q, libegl1-mesa, libegl1-mesa-dev, libegl1-mesa-drivers, libgles2-mesa-dev, libgles2-mesa
Description: RPI firmware (RPI2 compatible)
(at commit src f924320b83f29ee3110876f51929279d9a5b800a, commit xbian repo 2abfaccd1d1c5fc7441a78e6beb3602724a23dff)
root@kmxbibr ~ #

xbian-package-firmware provides libegl1-mesa (= 8.0.0), but required is version libegl1-mesa (= 13.0.6-1)

Ok, that's it. Will build xbian-package-firmware tomorrow