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Since the upgrade from to Xubuntu 16.04 from Xubuntu 15.10 on a Lenovo Thinkpad Twist (S230u) with Broadcom wireless card the wlan0 device has disappeared. It is as though the physical device was inexistent. How can it be re-activated ?
During the last step of the upgrade process I clicked NO regarding the question whether I wanted to deactivate UEFI Secure Boot. (I don't know whether this is a useful information).
The system is currently up to date.
sudo apt-get update sudo apt-get upgrade sudo apt-get dist-upgrade
--> finish with 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
--> only lists eth0 and lo.
--> contains a line "03:00.0 Network controller: Broadcom Corporation BCM43228 802.11a/b/g/n". But there is no mention of "wireless" or the like.
--> mentions eth0, wwan0, lo, each with no wireless extensions. Nothing else.
nmcli -f all device show
--> Same situation. GENERAL.DEVICE entries only for eth0, lo and cdc-wdm3 (which should be the mobile broadband device).
--> mentions under Additional drivers : Broadcom Corporation BCM43228 802.11a/b/g/n - Using Broadcom 802.11 Linux STA wireless driver source from bcmwl-kernel-source (proprietary).
I tried the solution suggested by David Foerster. But the re-installation process finishes with an error. The situation remains as it is:
lspci -nn -d 14e4: sudo apt-get purge bcmwl-kernel-source sudo apt-get update sudo apt-get update-pciids sudo apt-get install bcmwl-kernel-source
The result is:
Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: bcmwl-kernel-source 0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/1 515 kB of archives. After this operation, 8 013 kB of additional disk space will be used. Selecting previously unselected package bcmwl-kernel-source. (Reading database ... 259730 files and directories currently installed.) Preparing to unpack .../bcmwl-kernel-source_184.108.40.206+bdcom- 0ubuntu8_amd64.deb ... Unpacking bcmwl-kernel-source (220.127.116.11+bdcom-0ubuntu8) ... Setting up bcmwl-kernel-source (18.104.22.168+bdcom-0ubuntu8) ... Loading new bcmwl-22.214.171.124+bdcom DKMS files... First Installation: checking all kernels... Building only for 4.4.0-21-generic Building for architecture x86_64 Building initial module for 4.4.0-21-generic Done. wl: Running module version sanity check. - Original module - No original module exists within this kernel - Installation - Installing to /lib/modules/4.4.0-21-generic/updates/dkms/ depmod.... DKMS: install completed. modprobe: ERROR: could not insert 'wl': Required key not available update-initramfs: deferring update (trigger activated) Processing triggers for initramfs-tools (0.122ubuntu8) ... update-initramfs: Generating /boot/initrd.img-4.4.0-21-generic
Disabling validation via mokutil as described below didn't help either.