Unified kernel image

UKIs can run on UEFI systems and simplify the distribution of small kernel images. For example, they simplify network booting with iPXE. UKIs make rootfs and kernels composable, making it possible to derive a rootfs for multiple kernel versions with one file for each pair.

A Unified Kernel Image (UKI) is a combination of a UEFI boot stub program, a Linux kernel image, an initramfs, and further resources in a single UEFI PE file (device tree, cpu µcode, splash screen, secure boot sig/key, …). This file can either be directly invoked by the UEFI firmware or through a boot loader.
↫ Hugues

If you’re still a bit unfamiliar with unified kernel images, this post contains a ton of detailed practical information. Unified kernel images might become a staple for forward-looking Linux distributions, and I know for a fact that my distribution of choice, Fedora, has been working on it for a while now. The goal is to eventually simplify the boot process as a whole, and make better, more optimal use of the advanced capabilities UEFI gives us over the old, limited, 1980s BIOS model.

Like I said a few posts ago, I really don’t want to be using traditional bootloaders anymore. UEFI is explicitly designed to just boot operating systems on its own, and modern PCs just don’t need bootloaders anymore. They’re points of failure users shouldn’t be dealing with anymore in 2024, and I’m glad to see the Linux world is seriously moving towards negating the need for their existence.