Ok makes sense, just thought maybe someone has some secret sauce... Just for the sake of posterity here is what I was able to achieve so far:
I am able to get to the install screen using the iso after after installing UEFI on the board but then it blanks out
I am also able to make it work using .dtb following the debian instructions here:
https://wiki.debian.org/InstallingDebianOn/96Boards/HiKey960 (using the reference kernel in the bottom in order to make stuff work - so I guess not mainline...) and then transplanting centos aarch64 rootfs to that, i.e. only userspace tools (I think that's the term used?).
Finally, I can't donate a board :( but being creative, I may be able to set up remote access to mine if that would be helpful. I could have you ssh into a system that is connected to its serial console (via usb).
Cheers