Please help me identify which update disrupted my Wi-fi earlier this month

I’m not tech savvy (as will be demonstrated in a moment) but I’ve been running Ubuntu MATE on my primary everyday machine - a Samsung N220 netbook - for about a year (single partition, only one OS, clean installation, previously running Trusty) and it worked just fine. Here’s some basic system info:

Release 16.04.1 LTS (Xenial Xerus) 64-bit
Kernel Linux 4.4.0-71-generic x86_64
MATE 1.12.1
Memory: 982,0 MiB
Processor: Intel® Atom™ CPU N450 @ 1.66GHz × 2

[HISTORY] A couple nights ago, I noticed a warning icon from the update manager in the top bar, urging me to run $ SUDO APT-GET INSTALL -F in order to fix some broken dependencies or whatever, which I immediately did. In the output from apt-get I noticed a suggestion to run $ SUDO APT AUTOREMOVE in order to clean up some unnecessary stuff, which I did (possibly a terrible decision - I was quite sleepy at the time). I have no idea whether doing so is the cause of my problem, but that’s the only unusual thing I’ve done with my computer in a while.

[PROBLEM] Starting the next day, when I switched the netbook on, I noticed it couldn’t access the Internet via Wi-fi. Firefox will only load cached pages and PINGing google doesn’t return any output at all. I can’t even access my own router config page by typing its local address into Firefox, as I used to do: no data seems to get back to the computer from the outside world at all.
[NOTE] The problem only occurs when trying to access the wireless network. I’m currently plugged into the router via wire and everything’s working as it should.
[NOTE] The problem doesn’t seem to be with the router, as all other devices are still working normally with the Wi-fi, including another laptop also running Ubuntu MATE. Only this one computer (the one I’ve tampered with running apt-get and apt autoremove) is experiencing problems.

Can you smart, sexy, tech-savvy people help me out?

You sound savvy enough to me. I’m still running the rev-70 kernel, is that what your other (still-working) sytem is running?

The first thing that comes to mind is that the rev-71 kernel’s initramfs may be hosed up driver-wise.

The system you’re having trouble with, the Samsung, does it require a proprietary wifi device driver that could’ve gotten dropped erroneously in the latest update you applied?

Thanks for replying!

Looks like my other system is running rev-72.

Great question! But I don’t know the answer. Any ideas how I could find out?

Lemme think a minute… to start with check your system’s specs, basically anything from Broadcom is proprietary and needs special drivers. Also i think nvidia graphics cards always require them but that’s just repeated rumor, never had a nvidia device. Experience has taught me to prefer makers that prefer generic components, but mileage varies.

Then maybe check mate-control-center/hardware/additional drivers to see what’s in use.

Beyond that, whenever i’ve had to deal with manual driver installation i’ve resorted directly to google and taking step-by-step backups before trying things.

I updated my system yesterday to see if the rev-71 kernel might be hosed but the kernel had already been updated to rev-72. I’m wondering if another update to the rev-72 kernal might help.

Thanks a lot for trying to help.

Bad news: it didn’t.

You’d believe system specs for a non-custom laptop were easy to find online, but nope. Serves me well for using a 2nd hand computer, I suppose?
My best bet so far is a Qualcomm Atheros - based on this page, but mine is a (discontinued, I assume) NP-N220-JA02, not the still supported NP-N220P.

There’s something quite cryptic there:

Unknown: Unknown
This device is using an alternative driver.
° Using Processor microcode firmware for Intel CPUs from intel-microcode (proprietary)

Surprise new data!
I decided that the only way to go was reinstall from scratch, so I backed up all my data, then booted from CD (the same home-burnt Ubuntu MATE 16.04 DVD I’d originally installed from on both systems, the one troubling me and the one I’m currently posting from).

Interestingly enough, even when running from the live CD my Samsung netbook behaves exactly as above: it sees and ostensibly connects to the Wi-fi network, but then it cannot actually access the Internet through it (in fact, it apparently cannot reach any remote location, not even the router config page).

I’m trying hard to remember whether it behaved like that when I first installed from that CD last year, but I’m not quite sure. Tentatively, I’m imagining two different possible scenarios:

  • the proper, working drivers for my wireless board aren’t included by default on the live CD, but where auto-downloaded during or after installation by wired connection, and I’ve accidentally wiped them out messing with APT; or

  • something else is broken - possibly something hardware.

Does anybody have any clues? If not, I suppose I’ll focus on the 1st scenario (drivers) and re-install from scratch anyway, using a wired connection. What I dread, though, is that some part of the installation process might again wipe away the drivers, same as I manually did: it would be nice to understand exactly how to configure software updates in order not to have this happen.

Sorry, answer unknown. What i do is keep a backup copy of my system partition on the same drive. Once i have things as best they’re likely to get for a while, i update the backup. Etc. It makes it possible to move forward without taking too many steps backward.

That sounds like a really sensible thing to do. Thanks for the suggestion.

News: a clean re-install (with auto-updates) didn’t solve the problem. So it’s either something with the updates (kernel or drivers) or an actual hardware problem, I suppose.

SOLVED… in a way!

I performed another clean install from CD but, this time, I turned off updates while installing (in fact, I didn’t wire the laptop into the Internet)… And now Wi-fi is working! I’m writing from the problem laptop, via Wi-fi, right now.

I’m now running Linux Kernel 4.4.0-21-generic x86_64 out of the box. I haven’t performed any updates. Presumably, it was a recent update that broke my Wi-fi: which one could it be? It was something which got installed (or removed?) by running SUDO APT-GET INSTALL -F earlier this month, between the 1st and the 5th of April.

Can you help me? I’d like to identify the problem update so that I can block it and safely update everything else.

Hey, a history of apt is stored in /var/log/apt/history.log

Gives a history of the use of apt, with date and time. Hope that helps you identify what the problem was.

The current month’s apt usage is stored in history.log , archived months are stored in history.log.1.gz

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