networking - Broadcom Wireless Drivers unclaimed after installing update 16.04

I recently updated my Lenovo Y50 computer to 16.04. Since the update, I have been unable to see or connect to any wireless networks. The output of running sudo lshw -C network is:

*-network UNCLAIMED
description: Network controller
product: BCM4352 802.11ac Wireless Network Adapter
vendor: Broadcom Corporation

physical id: 0
bus info: pci@0000:08:00.0
version: 03
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress cap_list
configuration: latency=0
resources: memory:d1600000-d1607fff memory:d1400000-d15fffff

The fact that the wireless network controller is unclaimed leads me to believe that this is a driver related issue. I have checked and made sure that "Use proprietary driver" is checked in System Settings > Software & Updates > Additional Drivers and I have run sudo apt-get install --reinstall bcmwl-kernel-source I have also restarted after every driver change to finish the changes. Is there anything else I should try?

EDIT: Here is the result of running lspci -nnk | grep 0280 -A2:

08:00.0 Network controller [0280]: Broadcom Corporation BCM4352 802.11ac Wireless Network Adapter [14e4:43b1] (rev 03)
    Subsystem: Lenovo BCM4352 802.11ac Wireless Network Adapter [17aa:0623]

    Kernel modules: bcma, wl

Running sudo modprobe wl && dmesg | grep wl returns an error:

modprobe: ERROR: could not insert 'wl': Required key not available

modprobe: ERROR: could not insert 'wl': Required key not available

This is the subject of a recent and still open bug in Ubuntu: https://bugs.launchpad.net/ubuntu/+source/bcmwl/+bug/1572659 Please also see: Can't view Wifi networks after upgrading to Ubuntu 16.04

It appears that the only solution so far is to enter the computer's BIOS and turn off Secure Boot.

Secure Boot is a security standard developed by the PC industry to help make sure that your PC boots using only software that is trusted by the PC manufacturer

1) Turn off the secure boot

2) Remove bcmwl-kernel-source

sudo apt-get purge bcmwl-kernel-source

3) Re-install bcmwl-kernel-source .

sudo apt-get update
sudo apt-get install bcmwl-kernel-source

Reboot. Your wireless should now be working.