i worked on the BPI M1 Board (the first one) for quite a while now improving or more or less rewriting the A20 CSI camera driver.
there are no more artifact-ghost-frames any more.
The framerate goes from 5fps(full) to 120fps(crobbed small)
i also modified the camera-device driver for the ov5640.
disadvantage: existing camera device drivers would not be compatible any more.
maybe someone wants to give it a try and check it out.
it can be found here:
https://github.com/xenpac/OV5640-Sunxi-A20