A Guide to Installing AOSP Image using Fastboot

Understanding Fastboot and AOSP

Fastboot is a powerful tool that can control or modify an Android device's bootloader or recovery. It can be used to flash image files to devices or unlock their bootloaders. An important point is that the device's bootloader must accept Fastboot commands in order to use Fastboot.

What is AOSP?

AOSP (Android Open Source Project) refers to the open source projects for Android. While Android, the operating system for mobile devices, was developed by Google, most of its source code is available for anyone to view through AOSP. This allows developers to freely modify and improve the Android operating system's source code.

The Relationship Between Fastboot and AOSP

Fastboot and AOSP are important elements for developing and modifying Android systems. Fastboot is used to flash images built from AOSP onto devices. Therefore, understanding and knowing how to use Fastboot is an important skill for developing AOSP-based Android systems.

How to Use Fastboot

Fastboot is a command line tool that can be used in terminals or command prompts. Fastboot commands typically start with the word "fastboot" followed by commands that specify the action to execute. For example, the "fastboot flash" command is used to flash images to a device.

fastboot flash partition_name file.img

The above command flashes the image file "file.img" to the partition named "partition_name".

Building AOSP Images

After obtaining the AOSP source code, you need to build images using it. The build process can be executed with the following commands:

source build/envsetup.sh  
lunch aosp_arm64-eng
make -j4

The above commands set up the build environment, then build images using the "aosp_arm64-eng" configuration. The built images are saved in the "out/target/product/generic/" directory.

Verifying AOSP Images

Once the build completes, you can verify the generated images. In the "out/target/product/generic/" directory, you can find image files like "system.img", "boot.img", "userdata.img". These image files will later be flashed onto devices using Fastboot.

Installing Images Using Fastboot

After building the AOSP images, they need to be installed onto devices. Image installation can be performed using Fastboot.

Booting Device into Fastboot Mode

First, the device needs to be booted into Fastboot mode. By rebooting the device while holding certain key combinations, you can enter Fastboot mode. The key combination differs depending on device, so refer to your device's documentation for the exact method.

Installing Images Using Fastboot

After the device is in Fastboot mode, images can be installed using Fastboot. Images can be installed using the following commands:

fastboot flash boot boot.img  
fastboot flash system system.img
fastboot flash userdata userdata.img  

The above commands install "boot.img", "system.img", "userdata.img" onto the device, respectively.

Rebooting the Device

After all images have been flashed, the device needs to be rebooted. The device can be rebooted using Fastboot commands:

  
fastboot reboot

The above command reboots the device.

Verifying Installation Results

After the device reboots, verify that the installed AOSP image is functioning correctly. Check that the device boots up normally and the default apps run properly.

Post-Installation Verification and Troubleshooting

Verifying Installation

After installing the AOSP image, verify that the device boots up properly. Check that the Android screen appears and basic apps launch normally. If there are any issues, determine the cause and find solutions.

Troubleshooting

If issues arise after installing the AOSP image, the cause needs to be identified. The causes can vary. For example, there may have been errors during image building, or it could be a device hardware issue. After finding the cause, apply appropriate solutions. For instance, if errors occurred during image building, check the error messages and resolve the issues accordingly.

Common troubleshooting steps include:

• Checking log files for error messages or anomalies
• Verifying hardware compatibility
• Confirming images flashed properly
• Flashing images individually to identify cause
• Rebuilding images if necessary
• Searching online forums and Stack Overflow for similar issues and solutions

Getting help from other developers is also important for complex issues. Since troubleshooting can be very difficult, having adequate support allows more rapid and effective identification and resolution of problems.