Fixing Ubuntu with kernel 5.11

I previously mentioned the kernel 5.11 image was completely unusable. Well, these 2 were definitely missing and I need to install manually:

sudo apt-get install linux-headers-5.11.0-36-generic
sudo apt-get install linux-modules-extra-5.11.0-36-generic

The above took care of the networking unavailable issue for me. 

Now to get the display working with proper resolutions (no 640x480 please!)

sudo apt purge nvidia* libnvidia*

This removed my previously manually installed Nvidia display driver and after reboot it shows clearly it uses the X.Org open source driver instead of "Continue using a manually uninstalled driver" 

I hope this becomes stable for another few months. Keeping my fingers crossed.

Credits go to: Nvidia's official website (the post for fixing nvidia-smi >> Failed to initialize NVML: Driver/library version mismatch) 

This seems useful for installing Nvidia driver but I did not need to follow it. 

Ubuntu and GRUB default image

My Manjaro experiment has kinda failed because it would hang from time to time. Well, with Linux you always have workarounds, in this case, use the most "mainstream" distro: Ubuntu. I actually use a less resource intensive variant of Ubuntu called Ubuntu Mate. However, one of the updates must have broken compatibility with some existing drivers (e.g. NVIDIA Driver Version: 390.138) and I ended up always going back to the oldest kernel image which I choose manually from the Boot menu of GRUB. This is the guide to change the default so no more manual intervention is needed! (BTW, I was so worried that the Wifi driver is broken for some reason even in that image. It turns out the Wifi-disabled issue went away after hitting the "hardware" Wifi button on my machine a few times. Whew!)