The mezzanine card documentation you link is for a different product, sold separately. I used the one that comes with the Hikey960 which requires completely manual wiring. I got it to work in the end with some experimentation (and private help from an ex Linaro employee).
And yes, I did locate that aftermarket board and how to connect that. Documentation for the Hikey960 as sold today is what I was interested in.
About firmware. There are several links to different sets. E.g., https://github.com/96boards-hikey/tools-images-hikey960. Here there are 2 scripts and a subdirectory with a tempting name. I tried first recovery-flash.sh which appeared to work, then recovery-flash-uefi.sh (but the version of that script I got had hardwired and obviously incorrect paths, so I modified it). Still, it never ran to completion. I also tried issuing the commands manually looking at the scripts and following instructions scattered in the forums and on the web site.
Then there is the subdirectory install-prebuilt-uefi with a README and another script. I never tried that script. It is fragile documentation from my reading; if one god forbid connects things in a different order, ttyUSB0 and ttyUSB1 will get swapped, and things will become interesting!
Since I couldn’t find proper documentation of the process or the many files one flashed, I cannot intelligently debug the process. “Issue these commands” is not good in my worlds, I want “issue these command which have these intended effects” is what I need!
About WiFi. I did not locate that specific web page. I did find other pages (e.g. on the forum). The instruction I did locate did not lead to working interfaces (but magically disabled the USB-A ports!). There are claims in the forum that WiFi does not work yet for the Hikey 960 but just for the Hikey. There are some “try this” and “try that”, and somebody then claims that it works without explaining what he did to make it work.
There were also a bunch of unbelievable hardware issues with this board, contributing to the uselessness. (1) The bundled heatsink was about 15mm too high to fit in the bundled case. (2) The USB-A ports stopped working when when the board got warm during my WiFI struggles (I saw somewhere on he forum that others experience that too). (3) The adapter pin set needed for the mezzanine board didn’t have the same spacing as the 40-pin connector.
I notice that Amazon US has stopped selling this board, and I cannot say that I am surprised. Amazon UK still sells it, and that’s where I got mine.
I have worked with embedded development for a very long time. I have never come across something which causes the number off issues that this hardware + software + documentation does. I spent a full 12 hours on it without sufficient success. It is clear that I cannot use such a fragile product for my current project (which is optimising the GMP library for the A73). Even if I could coax it into working now, I expect it to cause an unacceptable maintenance burden during its lifetime.