GammaOS Android Firmware Build Instructions

Overview

This README outlines the steps to build the Android firmware for GammaOS, based on LineageOS 19. This is a Generic System Image (GSI) build process, suitable for various devices. Be aware, the repository size is approximately 300GB.

Prerequisites

• Computer: Recent x86_64 system (Linux, macOS, Windows; Ubuntu 20.04 LTS recommended).
• RAM: Minimum 32 GB.
• Storage: Minimum 300 GB (SSD recommended for faster build times).
• Java: OpenJDK 11 (included in source download).
• Python: Python 3 (python-is-python3).

Dependencies

Install the following build packages using your distribution’s package manager:

• bc bison build-essential ccache curl flex g++-multilib gcc-multilib git git-lfs gnupg gperf imagemagick lib32readline-dev lib32z1-dev libelf-dev liblz4-tool libsdl1.2-dev libssl-dev libxml2 libxml2-utils lzop pngcrush rsync schedtool squashfs-tools xsltproc zip zlib1g-dev

Building the Firmware

1. Clone the Repo: Ensure you are on the appropriate branch for your device.
2. Build Command: In the terminal, navigate to the root of the source code and issue: bash lineage_build_unified/buildbot_unified.sh treble nosync 64VN 64GN
3. Follow On-Screen Instructions: The build process will guide you through the remaining steps.

Note

This process will only build the system.img. The remainder of the process, including updating vbmeta keys, super images, and any boot or vendor partition updates, will be the responsibility of the user. I will give some general guidance on this below, but expect that you as the user understand what is required here.

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Creating or modifying the vbmeta image, as well as modifying boot and vendor images using the Android_boot_image_editor.

This tool supports parsing and re-packing of boot.img, vbmeta.img, vendor_boot.img, and more, supporting up to Android 13.

Prerequisites for Android_boot_image_editor

• JDK: JDK11 or higher.
• Python: Python 3.
• Dependencies:
  • Linux / WSL: sudo apt install git device-tree-compiler lz4 xz-utils zlib1g-dev openjdk-17-jdk gcc g++ python3 python-is-python3 p7zip-full android-sdk-libsparse-utils
  • Mac: brew install lz4 xz dtc
  • Windows: Install openssl and device-tree compiler with choco install openssl dtc-msys2

Modifying Vbmeta Image

1. Clone the Repository:

• git clone https://github.com/cfig/Android_boot_image_editor
• cd Android_boot_image_editor

2. Prepare vbmeta Image:

• If modifying an existing vbmeta.img, place it in the current directory.
• To create a new vbmeta.img, use avbtool. For example:

  avbtool make_vbmeta_image --output vbmeta.img --algorithm SHA256_RSA4096 --key /path/to/key_used_for_signing_or_pub_key
  

3. Unpack vbmeta Image:

• rm *.img
• cp <your_vbmeta_image> vbmeta.img
• ./gradlew unpack

4. Modify as Needed:

• Make necessary changes to the unpacked files.

5. Repack the Image:

• ./gradlew pack

6. Flash the Updated Image to Your Device (if applicable).

Modifying Boot or Vendor Images

1. Prepare Boot/Vendor Images:

• Place boot.img or vendor_boot.img in the current directory.

2. Unpack the Image:

• rm *.img
• cp <your_boot/vendor_image> vendor_boot.img
• ./gradlew unpack

3. Edit the Contents:

• Modify the files as needed in the build/unzip_boot directory.

4. Repack the Image:

• ./gradlew pack

5. Update vbmeta Image:

• If the vbmeta.img contains a hash of boot.img or vendor_boot.img, update the vbmeta image along with the boot/vendor image. Follow the steps in the "Modifying Vbmeta Image" section.

6. Flash the Updated Images to Your Device:

• Use the appropriate flashing tools and commands for your device.