R36S Android Build Environment (Docker)

This Docker environment provides a complete, reproducible build system for creating Android images for the R36S game console based on LineageOS 18.1.

Directory Structure

docker-build/
├── Dockerfile              # Docker image definition
├── docker-compose.yml      # Docker Compose configuration
├── build.sh               # Build script (runs inside container)
├── cache/                 # Mounted: stores .repo directory
├── results/               # Mounted: contains final ZIP files
└── README.md              # This file

Prerequisites

• Docker
• Docker Compose
• At least 200GB of free disk space
• 16GB+ RAM recommended
• Fast internet connection (first build downloads ~50GB of sources)

Quick Start

First Build

cd docker-build
docker compose up -d
docker compose logs

The first build will:

1. Build the Docker image (~10-15 minutes)
2. Initialize the repo and download sources (~1-2 hours depending on connection)
3. Build the Android system (~2-4 hours depending on CPU)
4. Generate the final ZIP file in results/ directory

Subsequent Builds

Subsequent builds are incremental and reuse:

• Cached source code in cache/.repo/
• Build artifacts in the container

Just run:

docker compose up -d
docker compose logs

Remember, this will take multiple hours (or even days on slow computers).

Configuration

Environment Variables

You can customize the build by setting environment variables in docker-compose.yml or via a .env file.

To use a .env file:

cp .env.example .env
# Edit .env with your preferred settings
docker compose up

REPO_SYNC_JOBS

Number of parallel jobs for repo sync (default: 4)

environment:
  - REPO_SYNC_JOBS=8

Or via command line:

REPO_SYNC_JOBS=8 docker compose up

Note: Higher values may be throttled by the remote server. Keep at 4 for initial sync.

BUILD_JOBS

Number of parallel jobs for compilation (default: nproc, all available CPU cores)

environment:
  - BUILD_JOBS=40

Or via command line:

BUILD_JOBS=40 docker compose up

Note: Uses all available CPU cores by default. Reduce if you need CPU for other tasks during build.

BUILD_TARGET

Build variant target (default: lineage_r36s-userdebug)

environment:
  - BUILD_TARGET=lineage_r36s-userdebug

LOCAL_MANIFESTS_BRANCH

Branch to use for local_manifests repository (default: main)

environment:
  - LOCAL_MANIFESTS_BRANCH=analog-stick-mouse

Or via command line:

LOCAL_MANIFESTS_BRANCH=analog-stick-mouse docker compose up

This allows you to use different device configurations or patches by selecting different branches from the local_manifests repository. For example, to use the analog-stick-mouse branch:

LOCAL_MANIFESTS_BRANCH=analog-stick-mouse docker compose up

Changing Sync Jobs

To prevent throttling, the default is set to 4 parallel jobs. If you have a fast connection and want to speed up the initial sync:

REPO_SYNC_JOBS=8 docker compose up

Build Output

After a successful build, you'll find the final ZIP file in:

docker-build/results/lineage-18.1-YYYYMMDD-HHMM-r36s-android.img.zip

This file can be flashed to your R36S device.

Troubleshooting

Out of Disk Space

The build requires significant disk space:

• Source code: ~50GB (cached in cache/)
• Build artifacts: ~100GB (stored in container)
• Final output: ~1GB (in results/)

Out of Memory

If builds fail due to memory issues, you can:

1. Increase Docker's memory limit
2. Reduce parallel jobs: BUILD_JOBS=20 docker compose up
3. For sync issues: REPO_SYNC_JOBS=2 docker compose up

Clean Build

To start fresh (this will re-download everything):

# Remove cached sources
rm -rf cache/.repo/*

# Remove results
rm -rf results/*

# Rebuild container
docker compose up --build

Debugging

To enter the container for debugging:

docker compose run --rm r36s-builder bash

Advanced Usage

Manual Build Steps

If you want to run build steps manually:

# Start container with shell
docker compose run --rm r36s-builder bash

# Inside container, run build commands manually
repo sync -j4
source build/envsetup.sh
lunch lineage_r36s-userdebug
mka -j$(nproc) bootimage systemimage
cd device/gameconsole/r36s
./mkimg.sh
mv *.zip /build/results/

Updating Sources

To update to the latest sources:

docker compose run --rm r36s-builder bash
# Inside container:
repo sync -j4
# Then exit and rebuild:
exit
docker compose up

Storage Management

Cache Directory

The cache/ directory stores the .repo metadata and git objects. This prevents re-downloading sources on each build.

Size: ~50GB after initial sync

To preserve this between builds, never delete cache/.repo/.

Results Directory

The results/ directory contains the final flashable ZIP files.

You can safely clean old builds:

rm results/*.zip

Technical Details

• Base Image: Ubuntu 24.04
• LineageOS Version: 18.1 (Android 11)
• Device Target: R36S game console
• Build System: AOSP/LineageOS build system
• Toolchain: GCC Linaro 6.3.1

Support

For issues with:

• The build process: Check the Android/LineageOS documentation
• The R36S device: Visit the andr36oid GitHub repository
• This Docker setup: Review the build logs and Dockerfile

Credits

• LineageOS Team: https://lineageos.org/
• andr36oid: https://github.com/andr36oid