What You'll Learn:

• Downloading the kernel source for your device (Samsung only)
• Understanding the kernel root & choosing the right compilers for compilation
• Customizing the kernel
• Remove Samsung's anti-root protections.
• Implementing KernelSU (to-do)
• Creating a signed boot image from the compiled kernel

What You'll Need:

• A working 🧠
• Ubuntu/Debian based PC/Server
• Knowledge of basic commands in Linux, and Bash/Shell script knowledge
• Understanding of English.
• Patience

• You can also use Gitpod if you don't want to install a Linux distro.
  • Keep in mind, though, that it might be more challenging for beginners who are not familiar with the command-line interface.
  • Access the terminal from Gitpod and its GUI using ravindu644/LinuxRDP.

sudo apt update && sudo apt install -y git device-tree-compiler lz4 xz-utils zlib1g-dev openjdk-17-jdk gcc g++ python3 python-is-python3 p7zip-full android-sdk-libsparse-utils erofs-utils \
default-jdk git gnupg flex bison gperf build-essential zip curl libc6-dev libncurses-dev libx11-dev libreadline-dev libgl1 libgl1-mesa-dev \
python3 make sudo gcc g++ bc grep tofrodos python3-markdown libxml2-utils xsltproc zlib1g-dev python-is-python3 libc6-dev libtinfo6 \
make repo cpio kmod openssl libelf-dev pahole libssl-dev libarchive-tools zstd --fix-missing && wget http://security.ubuntu.com/ubuntu/pool/universe/n/ncurses/libtinfo5_6.3-2ubuntu0.1_amd64.deb && sudo dpkg -i libtinfo5_6.3-2ubuntu0.1_amd64.deb

❗The video Guide for this tutorial can be found here : Open in Telegram

1. ✅ Downloading Part (Only for samsung)
2. ✅ Understanding the Kernel root
3. ✅ Understanding non-GKI & GKI kernels
4. ✅ Compiling Part (Universal for any device).
5. ✅ (❗ Samsung Specific) How to disable kernel securities from the menuconfig..?
6. ✅ How to make your kernel supports with APatch..?
7. ✅ Compilation Process.
8. ✅ (FINAL) How to put the compiled kernel, inside our boot.img..?

tar -xvf Kernel.tar.gz && rm Kernel.tar.gz

Note: It's a good idea to give the entire kernel directory 755 permissions to remove those 🔒 from the files and folders, preventing any issues when editing files and upstreaming the kernel.

Do it this way:

chmod +755 -R /path/to/extracted/kernel/

Before:

After:

The following video demonstrates all the steps mentioned above:

🎥 Extracting Samsung's Kernel.tar.gz & granting required permissions

• ⚠️ For other devices, You can find them by your OEM's sites or from your OEM's official GitHub repos.

+-------------------------------------+
|       Android Kernel Versions       |
+-------------------------------------+
|       non-GKI       |      GKI      |
+---------------------+---------------+
|         3.10        |      5.4      |
|         3.18        |      5.10     |
|         4.4         |      5.15     |
|         4.9         |      6.1      |
|         4.14        |               |
|         4.19        |               |
+---------------------+---------------+

• As you can see in the above screenshot, it's the Linux kernel source code.

• It must have those folders, highlighted in blue in the terminal.

• In GKI kernels, the kernel root is located in a folder named "common".

• If you have a GKI Samsung kernel, you should use the "common" kernel instead of "msm-kernel" for building your kernel, and the build steps are the same as for a non-GKI kernel. Refer to this repo for an idea.

• Before creating a build script, we must determine the compatible compilers we will use to build our kernel.

• Run make kernelversion inside the kernel root to check your kernel version.

• In my case, the kernel version is 5.4, which is GKI.

• You can find full information about choosing the correct compiler for your kernel version here (based on my experience, btw).

  • ❗Mediatek users, read this.

• Next, go to build_scripts, choose the appropriate script, download it, and place it inside your kernel's root directory.

• Keep in mind that you don't need to manually download any of these since my build scripts handle everything for you :)

• ❗If your device is Samsung Exynos, it doesn't support compiling the kernel in a separated 'out' directory. So, edit your build script like this

• Replace your_defconfig to your current defconfig which is located in arch/arm64/configs In GKI kernels, it's normally gki_defconfig

• But just in case, make sure to check arch/arm64/configs or arch/arm64/configs/vendor

• If your defconfig is located in the arch/arm64/configs directory, just replace your_defconfig with the name of your defconfig.

• If your defconfig is located in the arch/arm64/configs/vendor directory, replace your_defconfig like this:

  • vendor/name_of_the_defconfig
  • Example patch: here

• If you find these variables: REAL_CC or CFP_CC in your "Makefile", remove them from the "Makefile", then Search for "wrapper" in your Makefile. If there's a line related to a Python file, remove that entire line/function as well.

  • Example patch of removing the wrapper: click here

• Search CONFIG_CC_STACKPROTECTOR_STRONG and replace it with CONFIG_CC_STACKPROTECTOR_NONE

  • Example patch of fix -fstack-protector-strong not supported by compiler: click here

chmod +x build_xxxx.sh

./build_xxxx.sh

• When you run the script for the first time, it will begin to install all the necessary dependencies and start downloading the required toolchains, depending on your kernel version.

• Make sure not to interrupt the first run. If it gets interrupted somehow, delete the toolchains folder from "~/" and try again: rm -rf ~/toolchains

• Additional notes : Press space bar to enable/disable or enable as a module .

• Image :
  
  

• Image :
  
  

• If you can't find them (01 and 02) in the "→ Kernel Features", they are located in the "→ Boot options".

• Image :
  
  
• As I mentioned at the beginning of this guide, your must use your brain..! 🧠

• Image :
  
  

• Image :
  
  

• Image :
  
  

• Image :
  
  

• Image :
  
  
  
  ❗Additional Notes : To force load the vendor/system modules in some devices, use this commit (⚠️ This fixes various hardware related issues after installing a custom kernel) - Click here

• Image :
  
  

• Image :
  
  

• When you see "configuration written", stop the compilation process with Ctrl+C and replace the content of ".config" with your desired defconfig.

• ℹ️ The compiled kernel will be located at out/arch/arm64/boot.

• If you encounter errors during the compilation process, it's advisable to search for these errors on GitHub and find a solution.

- Use exact build number to download the firmware.

• Image :
  
  

  ---

• Kernel without GZIP compression :
  
  
• Kernel with GZIP compression :
  
  
  
  

• If your split_img has a boot.img-dtb + Uncompressed Kernel => Use "Image".
• If your split_img has a boot.img-dtb + GZIP compressed Kernel => Use "Image.gz".
• If your split_img don't has a boot.img-dtb + uncompressed Kernel => Use "Image-dtb". (if your out/arm64/boot folder don't have such a file, use Image instead)
• If your split_img don't has a boot.img-dtb + GZIP compressed Kernel => Use "Image.gz-dtb".

tar cvf "DEVICE NAME (APatch Support).tar" boot.img

• Proof :