To be frank, I am not good at troubleshooting network issues on my Ubuntu PC. But, one of the latest updates of Ubuntu forced me to do the same. My Wifi option suddenly disappeared from my settings when I restarted my PC.
This blog post explains how I fixed wifi issues on my Ubuntu 20.04 PC.
I tried some basic google search and got this solution. I executed the following command to find my wireless adapter.
sudo lshw -C network
From there I found out the network adapter model is starting with BCM43.
I executed following commands in terminal which are specific for BCM43 series network adapter.
sudo apt remove broadcom-sta-dkms bcmwl-kernel-source
sudo apt install firmware-b43-installer
Please note that you should have internet connected to execute the second command. I connected internet through USB tethering option of my Android phone.
After restarting my laptop, I was glad to see my wifi options are back on settings. Unfortunately, I stumbled upon another wifi issue. My saved wifi networks are not showing.
I restarted my search for solution and fortunately I found another solution here. I executed the following commands on terminal.
apt purge bcmwl-kernel-source
apt-get install broadcom-sta-source
apt-get install broadcom-sta-dkms
apt-get install broadcom-sta-common
And I rebooted my PC and found out Wifi networks are working properly. It was a huge relief for me to fix wifi issue of Ubuntu 20.04.