For what it's worth, I came back to a project I was working on trying to use OpenIndiana in a VM on XCP-ng 8.2 today and serendipitously, that project just released a new version 2024.04 on the same day. I gave the new ISOs a try and was able to boot into the installer and install it and then reboot into OI no problem. I tried both the GUI and text installers without an issue. I don't actually know what the difference is, but the release note does say "New Hardware Support" so I guess whatever that is worked! Not sure about other Illumos based distro; whether this is something later versions of them will pickup as well from their common base or if it's something that OI did specifically .