No good news to report. Today I got a new RAM stick - a Hynix model
which is listed at the POWER9 Hardware Compatibility page. And the
Blackbird refuses it as a "non-functional". So it's probably bad. My
Kingston sticks are refused because they cannot be configured (that may
be OK, they are simply too new to be supported).
So the result is that I still have complete computer but without RAM...
So as you may assume I'm posting this from my SGI O2 desktop.