Android 4 drivers different to Android 5/6/7 drivers?

[Stefan]

There is a lengthy explanation here, from someone who tried:

Android Lollipop 5.0 for the Fairphone 1

I have been working for quite some time on Android Lollipop 5.0 (specifically, CyanogenMod 12.0) for the Fairphone 1 and, finally, I am unveiling what I have done. But do not get too excited yet; this is not a fully functional Android Lollipop 5.0 at all. Hardware accelerated 3D graphics, sensors, basic GPS or Wi-Fi do work, but audio, telephony, Bluetooth, FM radio or camera do not (for a more detailed description see below). That is a letdown, I know. Another letdown for some of you will be …