Adding support for Banana Pi M2 Berry

Hi guys,
I'd love to help on this topic. I also own one of these board.
Mine is a slightly different version, the Banana Pi M2 Berry.
It does not change much. However, I can get Armbian to run on it, but not OpenWrt.
On this page, the links to download the SD card image are broken. Where do I find these files?
Should I compile it myself? But which branch should I use?
Thanks for any help.

Stay safe! Stay home!

What I did so far, I compiled a new version of OpenWrt that's available in the trunk (latest commit at that time 50a59b3a93)
It boots, but reboots after a few seconds.
Does anyone have an idea on how to track down this problem?
I don't know how to get any logs as there is no easy output to which I can connect.
Any help is appreciated.

There are new images available with kernel 5.4.x which work without the problem of restarting, wifi and mmc are also working, luck ...