Linux distributions commonly store bootable kernel artifacts under /boot, but UEFI and Boot Loader Specification layouts can also place artifacts on an EFI System Partition or extended boot partition mounted at paths such as /boot, /boot/efi, or /efi. Inspect mounts and loader configuration rather than assuming one universal path.
Kernel · Lesson 5
Kernel Location
Learn where distributions place kernel images, initramfs files, configuration, symbols, and versioned modules.
Versioned Files under `/boot`
A traditional distribution layout can contain:
vmlinuz-KERNEL_RELEASE: a bootable Linux kernel imageinitrd.img-KERNEL_RELEASEorinitramfs-KERNEL_RELEASE.img: early user-space imageconfig-KERNEL_RELEASE: configuration used for that packaged kernel buildSystem.map-KERNEL_RELEASE: symbol-address map from the kernel build
Names vary. An initrd-named file on a modern distribution often contains an initramfs archive. The vmlinuz naming convention does not tell you the exact internal compression or platform boot format; inspect it with distribution tooling.
What does a versioned vmlinuz-* file normally contain?
Initial RAM Filesystem and Build Metadata
The initramfs must contain the early modules and tools required by its matching kernel and root-storage design. A filename match is not enough; stale or failed generation can still produce an unusable boot entry.
config-* helps explain which features were built in, modular, or omitted. System.map-* can help symbolization and debugging, but address randomization, split debug information, and distribution tooling affect how it is used. These files are supporting artifacts, not alternate kernels.
Why is an initramfs tied to a particular kernel release and system configuration?
Versioned Kernel Modules
Loadable modules for the running release commonly reside below:
$ printf '/lib/modules/%s\n' "$(uname -r)"
On merged filesystem layouts this can resolve into /usr/lib/modules/KERNEL_RELEASE. Each installed kernel needs a compatible module tree and dependency indexes. modprobe uses release-specific metadata rather than searching arbitrary .ko files across the disk.
Which directory conventionally holds modules for the running kernel release?
Unified Kernel Images and Firmware Paths
A Unified Kernel Image, or UKI, is one signed EFI executable that can bundle a kernel, initrd, command line, and metadata. UKIs are commonly stored in an EFI-accessible boot location rather than represented by separate vmlinuz and initramfs files.
Therefore, an empty-looking traditional /boot layout does not prove that no kernel is installed. Use findmnt, the package database, boot-manager tools, and the loader's configuration to map the active artifacts.
What can a Unified Kernel Image combine?
Managing Space Safely
If the boot filesystem is full, first map mounted boot paths and query which package owns every artifact. Use the package manager's kernel cleanup workflow, preserve the running kernel and a known-good fallback, regenerate or inspect boot entries, and verify free space afterward.
Do not manually delete vmlinuz, initramfs, UKI, or module trees merely by age. A file can be the only bootable recovery entry even when it is not currently running.
Lesson complete
You finished Kernel Location
You can now map a kernel package to its boot and module artifacts.
Inspect actual
/bootand EFI-related mounts.Distinguish kernel image, initramfs, config, and symbol map.
Match module trees to the exact kernel release.
Account for Unified Kernel Images and distribution-specific layouts.
Reclaim boot space only through a verified package and fallback plan.
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