This have bugged me for quite some time, especially after any fresh installs or updates. I found a solution which worked perfectly for me. For those of you who have the same trouble with their laptop wifi [Toshiba or HP laptop-wifi-drivers in particular] this will surely help you.

1. Deactivate currently active Broadcom drivers from additional-drivers. Blacklist BCMA and BRCM80211 by typing in terminal:

   
   
   

   echo "blacklist bcma" | sudo tee -a /etc/modprobe.d/blacklist.conf
   
   echo "blacklist brcm80211" | sudo tee -a /etc/modprobe.d/blacklist.conf
   
   



2. Reboot now and download Synaptic Package Manager (makes it easier to find our files).


3. Search "bcm43" and download these 4 (they might prompt for some other dependency files - just accept them too)
   
   
   
   • bcmwl-kernel-source
   
   
   • broadcom-sta-common
   
   
   • broadcom-sta-source
   
   
   • firmware-b43-installer
     
   
   


4. Reboot


5. Now, you may check if your wifi is working (testing your hotspot or connecting to a network etc.)


6. If it isn't, then go to additional-drivers and activate the newly downloaded drivers followed by a reboot.

Note: additional drivers are found in System-settings > Software sources > additional drivers