Compiling the Kernel on a Mobile Device

Compared to a PC or server, ARM-based mobile devices come with meaningful constraints — performance, thermal throttling, and memory limits all make the experience noticeably different. That said, it is entirely doable.

This guide uses an Android-based mobile device as the reference platform.

If kernel compilation is your only goal, a mobile device offers far worse cost-efficiency than even a basic entry-level server. Make sure this is what you want before proceeding.

Note: This project does not natively support compilation under ARM architecture, if you have the need, you can only realize the support by modifying the project source code.

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Setting Up the Environment

Choose a Container Solution

Several options are available for running a Linux environment on Android:

Method	Notes
Proot	No root required, broadest compatibility, slightly lower performance
Chroot	Requires root, better performance
LXC	Requires root, near-native performance, good isolation
Docker	Requires root, convenient, depends on kernel support

Compatible terminal apps include Termux, Droidspaces, and others.

This guide uses LXC + Droidspaces.

Prepare a Rootfs

Ubuntu 24.04 ARM64 Rootfs is the recommended choice.

You can get a Rootfs using the following project:

• https://github.com/Droidspaces/Droidspaces-rootfs-builder

Build the Base Compilation Environment

After booting into the Rootfs, install the required dependencies:

apt update && apt upgrade -y
apt install gcc clang make git bison flex libssl-dev ccache cpio -y

The base environment is now ready.

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Compiling the Kernel

This example uses the LineageOS OnePlus SM8250 kernel on branch lineage-23.2.

Step 1: Get the Kernel Source

git clone -b lineage-23.2 \
  https://github.com/LineageOS/android_kernel_oneplus_sm8250.git \
  kernel_sm8250 --depth 1

cd kernel_sm8250/

Step 2: Generate the .config File

make ARCH=arm64 CC="ccache clang" O=out \
  vendor/kona-perf_defconfig vendor/oplus.config

Step 3: Build

make ARCH=arm64 CC="ccache clang" O=out \
  -j$(nproc --all) 2>&1 | tee error.log

Adjust the -j value to match what your device can handle. -j$(nproc --all) uses all available cores, but mobile devices running at full load for extended periods tend to throttle due to heat — sometimes a lower value like -j4 produces a more stable build.

On a OnePlus 8, expect an initial build to take roughly 30 minutes to 1 hour.

Done

Once the build completes, look for an Image entry in the log output — that confirms a successful build. On stock-based ROM devices, the image can be flashed and booted immediately for verification.