The lastest OSS modules (for sound) that worked where in TC8 32 bits [linux kernel 4.8.17].
which I tested in Virtualbox 6.06 under windows10-x64, today was working for HD Audio Intel emulation sound card, using osstest.
But the OSS in TC10 64bits is not working. The kernel modules seems to be OK, modprobe-ed them works, and lsmod shows them loading. My simulated HD Audio Intel is the same.
I saw no /lib64 folder so I created one and simlinked it to /lib.
There is no folder /dev/dsp and /dev/oss is empty.
Reading the wiki, I tried
sudo ossdevlinks -r -v
sudo ossdetect -d -v
...but still no sound. alsa modules were never loaded by mistake, no firefox, just used fifth browser.