Meanwhile one can pin PPA to prevent upgrades:

$ cat /etc/apt/preferences.d/coolpi-ppa-priority Package: * Pin: release o=LP-PPA-george-coolpi-mali-g610 Pin-Priority: 2000 Package: * Pin: release o=LP-PPA-george-coolpi-multimedia Pin-Priority: 2000 Package: * Pin: release o=LP-PPA-george-coolpi-rknpu Pin-Priority: 2000

@george got it, thanks! Looking forward for proper wiring solution. Meanwhile, I'll try to put together some custom wiring.