Ubuntu – Wireless connection stopped working and ifconfig no longer shows wlan0

broadcom

I'm running Ubuntu 16.04 LTS on a laptop with a Broadcom wireless adapter. The connection has been finicky in the past, but as of today has completely failed.

ifconfig shows only a loopback interface, no wlan0 or eth0. rfkill list all shows wlan and Bluetooth with neither soft or hard blocks.

lspci -vnn | grep Network shows

01:00.0 Network controller [0280]: Broadcom Corporation BCM4352 802.11ac Wireless Network Adapter [14e4:43b1] (rev 03)

As well as

Subsystem: Lenovo BCM4352 802.11ac Wireless Network Adapter [17aa:0623]

When booting my laptop I had an internal error message which I chose to report, and saw it was an issue with my wireless driver bcmwl-kernel-source, with the message "avahi-daemon crashed with SIGABRT in avahi_malloc ()". Following a suggestion online, I tried systemctl restart avahi-daemon which did not fix the issue, but removed the error message. (For better or worse. I can no longer see the specifics of the message.)

Other things I've tried:

  • sudo service network-manager restart

  • tethering with my android phone hotspot via USB to connect to internet (the network manager UI changed from "no network devices available" to "ethernet – device not managed")

  • disabling and reenabling the proprietary driver bcmwl-kernel-source listed under software & updates > additional drivers.

I'm familiar with the guide on here for finding Broadcom drivers, but I suspect there is another issue and would like feedback before messing with drivers. (I would link the question/answer but paste no longer works on my android phone…).

One more thing to note. I have a hard key for airplane mode, which normally toggles networking on or off in the drop down networking menu. It now does not toggle networking in the menu, but puts a soft block on my wlan device, shown by rfkill list all.

What might be the issue? Even an unrelated offline 3rd party software I use won't run since it can no longer verify my MAC address. Thanks for any suggestions.

update

modinfo wl returns ERROR: module wl not found. I ran
sudo apt-get purge bcmwl-kernel-source and attempted a reinstall. I received an error during the install identical to this one (but in English). Each attempt to reinstall the driver causes a crash report since module wl is missing.

I reinstalled linux-headers-generic as suggested in the response here then reinstalled bcmwl-kernel-source, and still no success.