PIXEL 7A Kernel

Building And Flashing AOSP KERNEL for Pixel 7A (Lynx)

Objective

The Aosp kernel is to be integrated with our own AOSP build for the operations which can be done with kernel level.

Downloading Sources with Branch

For downloading the sources for kernel we are using the Repo Tool and Create a directory and change to that directory by using below commands

mkdir Kernel_Root/ && cd Kernel_Root/

Open the Kernel_Root directory in the terminal window and initialize the Repo tool in this directory by using following command

For Kernel Branches visit this Google kernel.

repo init -u https://android.googlesource.com/kernel/manifest -b android-gs-lynx-5.10-android13-qpr3

After Repo initialization you need to download the source code by using the following command.

repo sync -j16

NOTE

The above command will take significant time depends upon the Internet speed and system configuration.

Changing the Android Kernel Name

NOTE

Execute the all the commands in Kernel_Root/ directory.

Identify the Following File. Kernel_Root/build/build.sh

cd build

gedit build.sh

After opeining the file find the -e LTO_CLANG_FULL and add the below lines after the above line.

-d LOCALVERSION_AUTO \

--set-str LOCALVERSION "--Lynx-PIXEL_7A--" \

Compiling The Android Kernel

To compile the kernel execute the following command.

LTO=full BUILD_AOSP_KERNEL=1 ./build_lynx.sh

NOTE

The above command will take significant time depends upon the Internet speed and system configuration.

Embedding Kernel Image File into AOSP source Code

Integrating Compiled Android kernel onto the AOSP build.

Initializing the AOSP_Root

Open the AOSP_ROOT directory in Terminal and Execute the following commands

cd AOSP_ROOT/

source build/envsetup.sh

lunch

lunch command will list out all the available devices targets, you need to select the the device which your building for. (In my case it is Pixel 7a (Lynx)),so i will select aosp_lynx-userdebug.

Copying Kernel Image files to AOSP

Now copy all files in Kernel_Root/out/mixed/dist/ to the AOSP_Root/device/google/lynx-kernel/ directory.

NOTE

Before copying all files take the backup of all files for in future if you want to revert back the changes.

changing the Prebuilt boot image path

Identify the file named BoardConfig-common.mk in the path AOSP_Root/device/google/gs201/ open the file and identify the following lines in the file

BOARD_PREBUILT_BOOTIMAGE := $(wildcard $(TARGET_KERNEL_DIR)/boot.img)

ifneq (,$(BOARD_PREBUILT_BOOTIMAGE))

TARGET_NO_KERNEL := true

else

TARGET_NO_KERNEL := false

endif

Delete the Highlighted lines from the file and save the file and close it after deleting the file look like.

TARGET_NO_KERNEL := false

by doing above change it won't refere to prebuilt boot.img instead it will create with our own boot.img

Building The AOSP Image file with Kernel

Now execute the following command to build the new AOSP build Image.

make updatepackage -j16

With above command new AOSP Build Image is created in the following path AOSP_Root/out/target/product/lynx/ with file name aosp_lynx-img-eng.cdac.zip . The zip can flashed on to the mobile.

Flashing AOSP Image Files to the Device.

To flash the AOSP Images Execute the following commands in AOSP_Root/ directory.

To go into Bootloader mode execute the following command

adb reboot bootloader

To flash the AOSP Image files execute the following command.

fastboot -w update out/target/product/lynx/aosp_lynx-img-eng.cdac.zip

Verification

to verify the Kernel is flashed or not connect the device to host system and execute the following commands in the terminal.

adb shell

now you will be in the shell of your device and then type your command without $ symbol.

 uname -a

It will display the Kernel version string with your kernel name and version as shown below.

Linux version 5.10.157--Lynx-PIXEL7A-+