If you are an Android developer or enthusiast, you might have heard of kernel zips. Kernel zips are flashable files that contain the kernel image and other related files for a specific device. Kernel zips can be used to update, customize, or tweak the performance of your Android device. But how do you make a kernel zip In this article, we will show you the steps to create a kernel zip from scratch.
What You Need
Before you start making a kernel zip, you need to have some prerequisites ready. Here are the things you need:
A Linux-based computer or a virtual machine with Linux installed.
A toolchain to compile the kernel source code. You can use any toolchain that is compatible with your device's architecture and kernel version. For example, you can use the Google Android Clang toolchain or the Linaro GCC toolchain.
The kernel source code for your device. You can get it from the device manufacturer's website, GitHub, or XDA Developers. Make sure you download the correct branch and tag for your device's model and Android version.
A text editor to edit the kernel configuration and other files.
A zip utility to create the zip file.
A device with an unlocked bootloader and a custom recovery installed.
Step 1: Compile the Kernel Image
The first step is to compile the kernel image from the source code. Here are the steps to do it:
Open a terminal and navigate to the folder where you extracted the kernel source code.
Run the following command to set up the environment variables for your toolchain:
export ARCH=arm64 #change this according to your device's architecture
export CROSS_COMPILE=/path/to/your/toolchain/bin/aarch64-linux-android- #change this according to your toolchain's prefix
export PATH=$PATH:/path/to/your/toolchain/bin #add your toolchain's bin folder to your path
Run the following command to clean up any previous build files:
make clean && make mrproper
Run the following command to load the default kernel configuration for your device:
If you want to customize the kernel configuration, run the following command to open a menu-based interface:
Once you are done with the configuration, run the following command to start compiling the kernel image:
make -j$(nproc --all)
If everything goes well, you should see a file named Image.gz-dtb in the arch/arm64/boot folder. This is your kernel image file.
Step 2: Create the Kernel Zip
The next step is to create the kernel zip file that can be flashed on your device. Here are the steps to do it:
Create a new folder and name it anything you want. This will be your kernel zip folder.
Copy the Image.gz-dtb file from the arch/arm64/boot folder to your kernel zip folder.
Create a new folder inside your kernel zip folder and name it META-INF. This folder will contain some metadata files for your kernel zip.
Create another folder inside the META-INF folder and name it com. Inside this folder, create another folder and name it google. Inside this folder, create another folder and name it android. This is the standard folder structure for Android zip files.
Create a text file inside the META-INF/com/google/android folder and name it update-binary. This file will contain the script that will run when you flash your kernel zip. You can use any scripting language that is supported by your custom recovery, such as shell script or Edify script. Here is an example of a simple shell script that will flash your kernel image: