well, that was fantastic. i grabbed the latest Armbian images for the Khadas VIM2 (another S912-based SBC), grabbed the kernel from them and put it under the Void userspace.
on the plus side, it did boot. and it might be the first time i've ever seen the Mali T820 initialise properly in dmesg!
on the minus side, though, X doesn't work:
Fatal server error:
[ 826.091] (EE) Cannot run in framebuffer mode. Please specify busIDs for all framebuffer devices
i don't quite know what that message means, but i'm fairly sure the kernel now somehow lacks support for modesetting
well, i don't know what fixed it - but i just went through and added myself to every single group, and suddenly that seemed to fix it... except for the screen coming up at 1920x1080. oops! a quick xrandr fixed that
...and we have genuine accelerated OpenGL! (ok, not very accelerated... but it's still faster than the Pi400)
@millihertz Oh, yes, you might have needed write access to dri file under /dev. Usually udev fixes ownerships and permissions for you, but if you used custom kernel something might have gone wrong.
@m0xee the weird thing is, it didn't work when i tried it as root...