Before you can build for any target, you need the kernel source. To get the kernel source, you need Git. Begin by installing Git on your device, if you don’t already have it:

Next, download the source code for the latest Raspberry Pi kernel:

This can take several minutes.

Now that you have the kernel source, build a fresh kernel natively or via cross-compilation.

This guide assumes that your Raspberry Pi runs the latest version of Raspberry Pi OS.

First, install the build dependencies:

First, you will need a suitable Linux cross-compilation host. We tend to use Ubuntu; since Raspberry Pi OS is also a Debian distribution, compilation commands are similar.

The menuconfig tool requires the ncurses development headers to compile properly. To install these headers, run the following command:

Next, download your kernel sources. In particular, ensure you have installed the default native configuration or default cross-compilation configuration.

Once you’ve got everything set up, you can compile and run the menuconfig utility as follows:

To cross-compile a 64-bit kernel:

To cross-compile a 32-bit kernel:

To navigate the menuconfig utility, use your keyboard:

After a brief compilation, menuconfig presents a list of submenus containing all the options you can configure. There are many options, so take your time to read through them. Resist the temptation to enable or disable a lot of things on your first attempt; it’s relatively easy to break your configuration, so start small and get comfortable with the configuration and build process.

Once you’re done making changes, press Escape until you’re prompted to save your new configuration. By default, this saves to the .config file. You can save and load configurations by copying this file.

After customising, you should now be ready to build the kernel.

To check the kernel version currently running on your device, run the following command:

Always check your version of the kernel before applying patches. In a kernel source directory, run the following command to see the kernel version:

You should see output similar to the following:

In this instance, the sources are for a 6.1.38 kernel.

The application of patches depends on the format used to distribute the patch.

Developers distribute most patches as a single file. Use the patch utility to apply these patches. The following commands download, uncompress, and patch our example kernel version with real-time kernel patches:

Some developers distribute patches in the mailbox format, a folder containing multiple patch files. Use Git to apply these patches.

To apply the mailbox formatted patches with Git, run the following command:

Always follow the instructions provided by the patch distributor. For instance, some patchsets require patching against a specific commit.

First, fork the Raspberry Pi kernel repository and clone it to your development device. You can then make your changes, test them, and commit them into your fork.

Then, submit a pull request containing your changes to the Raspberry Pi kernel repository. Raspberry Pi engineers will review your contribution and suggest improvements. Once approved, we’ll merge in your changes, and they’ll eventually make their way to the stable release of the Raspberry Pi kernel.

First, clone the Linux kernel tree to your development device. You can then make your changes, test them, and commit them into your local tree.

Once your change is ready you can submit it to the Linux kernel community. Linux kernel development happens on mailing lists, rather than on GitHub. In order for your change to become part of Linux, please email it to the community as a patch. Please follow Submitting patches: the essential guide to getting your code into the kernel and Linux kernel coding style in the Linux kernel documentation. Linux kernel contributors will review your contribution and suggest improvements. Once approved, they’ll merge in your changes. Eventually, they’ll make their way into a long-term release of the Linux kernel. Once we’ve tested that long-term release for compatibility with the Raspberry Pi kernel, your changes will make their way into a stable release of the Raspberry Pi kernel.