Wi-Fi Problem Ubuntu 18.04 USB Boot on MacBook Pro

Always wanted to try Ubuntu but didn't want to risk changing anything in your machine? Well the community has thought about this. They termed it as live run, basically having the whole OS running from a CD, DVD, USB or any portable device you could think of, no installation needed. There are quite a few tutorials explaining how to do this, so I won't bother repeating it here. This tutorial is a good one to get it on any USB stick. I chose USB because that's what I had near me.

Booting from USB works like a charm, everything seems to work except the Wi-Fi! What can a machine do without internet these days? I looked into the Wi-Fi Settings and it's telling me it couldn't find a Wi-Fi adapter.

Unfortunately I don't have an extra machine to google for solution, so I had to use the good old Ethernet cable to connect to internet and that fortunately worked, I don't know what I would do if I had one of those thin laptops. Anyway if you google Ubuntu Wi-Fi problem, it will get you hundreds of hits... seems like this is a well-known problem and my research narrowed it down to missing driver.

To know what you're missing, the first thing you need to do is identify the network card you have. The command in Linux is lspci -vvnn | grep -A 9 Network.

   ubuntu@ubuntu:~$ lspci -vvnn | grep -A 9 Network
   02:00.0 Network controller [0280]: Broadcom Limited BCM4331 802.11a/b/g/n [14e4:4331] (rev 02)
      Subsystem: Apple Inc. AirPort Extreme [106b:00f5]
      ...
      Latency: 0, Cache Line Size: 256 bytes
      Interrupt: pin A routed to IRQ 17
      Region 0: Memory at a0600000 (64-bit, non-prefetchable) [size=16K]
      Capabilities: 
      Kernel driver in use: bcma-pci-bridge
      Kernel modules: bcma

This means I have:

• The Chip ID: BCM4331
• The PCI-ID: 14e4:4331
• Kernel driver in use: bcma-pci-bridge

Fortunately I can see I don't have wl driver, this is easily remedied by installing bcmwl-kernel-source

   sudo apt install bcmwl-kernel-source

My Wi-Fi works afterwards.

If you're not as lucky as I am, knowing your network card is a first step to google for some more solution.

My MacBook Pro spec: macOS High Sierra, 2.9 Ghz Intel Core i7, 8 GB 1600 MHz DDR3