This fixed blank screen, clock syncing, kodi crashing, chromium crashing, video slow. Don't use synaptic
1 sudo apt-get update sudo apt-get upgrade
2 sudo apt-get install -f libxfont2
3 sudo dpkg -i xserver*.deb download the two common/core files below and install using dpkg to the left.
wget https://github.com/rockchip-linux/rk-rootfs-build/blob/master/packages/armhf/xserver/xserver-xorg-core_1.19.3-1_armhf.deb?raw=true()
wget https://github.com/rockchip-linux/rk-rootfs-build/blob/master/packages/armhf/xserver/xserver-common_1.19.3-1_all.deb?raw=true
4 update/upgrade again
5 sudo apt --fix-broken install if package is broken. Reboot.