I own quite a bit of laptops. Four Thinkpads (X201, X220, X230, T420) and a Dell (M3800). Recently after my Ubuntu 14.04 broke down, and as my code’s dependence on ROS lessened, I decided to upgrade my Dell M3800’s version from 14.04 to 15.10. Well, well, well… Not everything went smoothly.

Actually one thing did not go as planned. The supposedly “Ubuntu-supported’ M3800 had issues with its wireless card firmware. The specific card that my M3800 has is the Intel AC7260. Below is the fix that I had to conduct to get it working again, which is very simple. This really should be fixed right out of the box Ubuntu…

1. Download the latest drivers
   1. https://wireless.wiki.kernel.org/en/users/drivers/iwlwifi
2. Update the firmware
   1. Assuming you downloaded the following:
      1. https://wireless.wiki.kernel.org/_media/en/users/drivers/iwlwifi-7260-ucode-15.227938.0.tgz
   2. Unzip in the downloaded folder
   3. Run in command line:
      1. sudo cp iwlwifi-7260-15.ucode /lib/firmware/

Running the above and updating the firmware helped as now upon boot, the M3800 connects very quickly to a nearby hotspot.