Thanks Nick. In the meanwhile, would dtbo overlay, setting up CSI taken from radxa's github a733, work with kernel/u-boot of your image?
Is there a way I can manually alter boot files to get this dtbo loaded?
This is of course for the experiment - radxa's a733 image seems to still have a problem with ISP processor (or dtbo file affecting data formatting), as the resulting picture from the camera seems to be in a wrong color space (by the look, but I'm not an expert).
I've reported the issue at https://forum.radxa.com/t/radxa-cubie-a7a-radxa-13m-214-camera/29717/7 for anyone interested.