Need to admit, didn't pay attention if WiFi was available right from the start or not, was concentrated on other stuff. Cleared the SD card again and tried the image at arm-files.devuan.org, but failed it to complete boot process, was trying to run some script again and again (suppose the init script).

Restarted with the image at https://github.com/pyavitz/rpi-img-buil … tag/images, booted so far, `ip addr` seems to reveal two adapters, not fully sure, though, as console prints several characters at the left out of the screen (how to fix?). Once network is set up correctly that won't disturb me too much any more as I'll be accessing the RPi via ssh anyway...

Didn't find the first image in the forum history any more (the one with root + toor login), so cannot tell if that would had recognised the wlan card right from the beginning.