Just to wrap things up, the solution turned out to be adding
/boot/config.txt containing

dtparam=audio=on

as the only entry. After reboot audio works as before.

bob prohaska

bob prohaska  wrote:
> I R A Darth Aggie  wrote:
>>
>> Well, now, that's a/the problem. Try this:
>>
>> sudo modprob snd_bcm2835
>>
>
> [thinking you meant modprobe, with an e at the end]
>
>
>
> bob@raspberrypi:/boot $ sudo modprobe snd_bcm2835
> bob@raspberrypi:/boot $
>
> There are a bunch of bcm2835* items in /boot:
> bob@raspberrypi:/boot $ ls *2835*
> bcm2835-rpi-a.dtb       bcm2835-rpi-b.dtb       bcm2835-rpi-b-rev2.dtb
> bcm2835-rpi-a-plus.dtb  bcm2835-rpi-b-plus.dtb  bcm2835-rpi-zero.dtb
> but nothing specific to the Pi3.
>
> It looks like the driver got deleted in the course of the last
> upgrade. I was prompted to delete unnecessary files, and did so.
> Bad move, looks like.
>
> Apt-get update/upgrade insist everything is at its latest and
> greatest. Is there a way to forcibly install the correct sound
> drivers?
>
> With my thanks!
>
> bob prohaska
>

--- SoupGate-Win32 v1.05