My Wifi disappeared

It happened yesterday. 1 day later after my laptop was open to upgrade RAM. So it shouldn't be because of this.

I saw how the Wifi got disconnected. It couldn't see any Wifi networks around. And then the entire adapter disappeared. I have dialed with Wifi drivers a few times already so it wasn't very stressing for me. But after I tried reinstalling the driver as I wrote in this post probably more than 10 times and it didn't work, I got very desperate. I started questioning my skills and then my existence. This is normal for a developer - an usual phase when you fight with something :D

Here is the dmesg error:

Troubleshooting Intel Wifi Adapter on Debian:

• rfkill - shows if a hardware is blocked on a software level or on a hardware level.
• lshw - shows detected hardware on the machine
• lsmod - shows installed drivers/modules
• ip a - shows network interfaces - the Wifi one was missing there.

I installed the backports version of iwlwifi: https://packages.debian.org/stretch-backports/firmware-iwlwifi

Nothing worked. 6 hours of struggle. 6 hours of reinstalling drivers and restarting. 6 hours of searching on internet and reading forums.

There was an update waiting for me in the software update app. It showed linux-image for an update which I, for some reason, ignored. But then I updated it. The update got stuck for almost 1 hour before I realized it was stuck. Ctrl + Alt + Dell. It started. No Wifi. There was a new update on the kernel though. Apparently there has been a Debian update 2 weeks ago: https://www.debian.org/News/2020/20200509

Here is the stuck update:

I tried Debian live USB. The Wifi didn't work. Reinstalled the driver on the USB remembering it was working before this way. Nope. It didn't work.

I tried Ubuntu live USB. Ubuntu starts with everything working. Nope. There was no driver there. Reinstalled the driver. It worked. Which was a pretty clear sign the Wifi card was working properly. So the hardware was fine.

Rebooted the computer in Debian - the Wifi was there, working. So I am asking WTF? What made it disappear for 1 day making me pulling my hair in a desperation and then just appeared like it never got lost asking me "What's up?".

Any ideas what happened? I have no ideas at all.

I suspect the Debian update that probably has been in a stage before install. No idea.