Iot-protocolsHow-ToIntermediate · 4 min read

How to Compile Kernel for Raspberry Pi: Step-by-Step Guide

To compile the kernel for Raspberry Pi, first clone the Raspberry Pi Linux kernel source with git, then configure it using make bcmrpi_defconfig or a similar config, and finally build it with make -j$(nproc). After compiling, copy the kernel and modules to your SD card's boot and root partitions.

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Syntax

Here is the basic syntax to compile the Raspberry Pi kernel:

git clone --depth=1 https://github.com/raspberrypi/linux - Downloads the kernel source.
make bcmrpi_defconfig - Sets default config for Raspberry Pi 1 (use bcm2711_defconfig for Pi 4).
make -j$(nproc) - Compiles the kernel using all CPU cores.
make modules_install INSTALL_MOD_PATH=../modules - Installs kernel modules to a folder.

bash

git clone --depth=1 https://github.com/raspberrypi/linux
cd linux
make bcmrpi_defconfig
make -j$(nproc)
make modules_install INSTALL_MOD_PATH=../modules

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Example

This example shows how to compile the kernel for Raspberry Pi 4 and prepare the files for the SD card.

bash

git clone --depth=1 https://github.com/raspberrypi/linux
cd linux
make bcm2711_defconfig
make -j$(nproc)
make modules_install INSTALL_MOD_PATH=../modules

# Copy kernel and modules to SD card (mounted at /mnt)
sudo cp arch/arm64/boot/Image /mnt/boot/kernel8.img
sudo cp -r ../modules/lib/modules /mnt/lib/

# Update firmware files if needed
sudo cp -r ../modules/lib/firmware /mnt/lib/

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Common Pitfalls

Wrong config: Using bcmrpi_defconfig for Pi 4 will cause boot failure. Use bcm2711_defconfig for Pi 4.
Missing dependencies: Kernel build needs packages like bc, build-essential, and libncurses-dev. Install them first.
Incorrect module install path: Always set INSTALL_MOD_PATH to a temporary folder before copying to SD card.
Not cleaning old builds: Run make clean if you rebuild to avoid conflicts.

bash

## Wrong config example (Pi 4 boot fails):
make bcmrpi_defconfig

## Correct config for Pi 4:
make bcm2711_defconfig

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Quick Reference

Summary tips for compiling Raspberry Pi kernel:

Clone kernel source with git clone --depth=1 https://github.com/raspberrypi/linux
Choose correct config: bcmrpi_defconfig (Pi 1), bcm2709_defconfig (Pi 2/3), bcm2711_defconfig (Pi 4)
Install build tools: sudo apt install bc build-essential libncurses-dev
Use make -j$(nproc) to speed up compilation
Copy kernel and modules to SD card boot and root partitions

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Key Takeaways

Clone the Raspberry Pi kernel source from the official GitHub repository.

Select the correct default config for your Raspberry Pi model before compiling.

Install all necessary build dependencies to avoid errors during compilation.

Use all CPU cores with make -j$(nproc) to speed up the build.

Copy the compiled kernel and modules properly to your SD card for booting.