In this step-by-step tutorial, we’ll walk through the entire process of building a custom Linux kernel, creating a minimal filesystem using Busybox, running it on QEMU, and debugging the kernel. Finally, we’ll wrap up by learning how to compile and add custom Linux kernel modules to enhance our kernel. I’m using a Linux system for this demonstration, specifically Ubuntu 16.04.7 LTS with kernel version 4.15.0-142-generic. However, the steps should be similar for other Linux distributions.