Today I found some time to dig deeper into the Bananapi and it’s startup. In our baalue_sdk@github repo (https://github.com/tjohann/baalue_sdk) you can find all bootloader related stuff (https://github.com/tjohann/baalue_sdk/tree/master/common) and also a working kernel config (https://github.com/tjohann/baalue_sdk/tree/master/configs).
For a short howto see https://github.com/tjohann/baalue_sdk/tree/master/Documentation
See below for a screenshot: