Comment # 3 on bug 1090458 from Takashi Iwai

Thanks.  Also, could you give the full dmesg output when WiFi crashes?

TW repo doesn't keep the old packages, unfortunately.  Sometimes one older
version may remain for some time, but it's not persistent.

So, for testing purpose, now I'm building the last 4.15.x openSUSE kernel in
OBS home:tiwai:kernel:4.15 repo.  It'll take some time (an hour or so), and
give it a try later.

Getting the older kernel-firmware is also tricky, you'd need to rebuild too. 
Maybe we should begin with checking which packages have been updated.

Do you remember about which date the WiFi worked?  You can take a look at
/var/log/zypp/history and see which kernel-default and kernel-firmware packages
have been updated.