grapheneos-flasher 0.3.0

Automated GrapheneOS flashing with security verification

GrapheneOS Flasher

A Python tool that automates the download, cryptographic verification, and flashing of GrapheneOS factory images.

It follows the official CLI installation guide step-by-step and surfaces clear, actionable prompts at each stage so you always know what is happening and why.

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Requirements

Tool	Version	Purpose
Python	3.14+	Runtime
OpenSSH (ssh-keygen)	any	Signature verification
Android platform-tools (fastboot, adb)	35.0.1+	Device communication

Install platform-tools: Download from developer.android.com and add the extracted directory to your PATH.

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Installation

From PyPI (recommended)

uv tool install grapheneos-flasher
# or
pip install grapheneos-flasher

Then run:

grapheneos-flasher <device_codename> [options]

From source

git clone https://github.com/264nm/grapheneos-flasher
cd grapheneos-flasher
uv sync
uv run grapheneos-flasher <device_codename> [options]

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Usage

Download and verify only (safe — no device changes)

uv run grapheneos-flasher shiba

Downloads the latest factory image and signature, verifies the cryptographic signature against GrapheneOS's public key, and extracts the archive. Prints manual step-by-step instructions at the end. Nothing is written to your device.

Flash GrapheneOS (installs the OS, wipes all data)

uv run grapheneos-flasher shiba --flash

Runs through download → verify → extract, then presents a pre-flight checklist and walks you through the flash interactively. The tool handles unlocking and re-locking the bootloader automatically.

Flash without bootloader management

uv run grapheneos-flasher shiba --flash --no-bootloader-mgmt

Skips automatic unlock/lock. You must run fastboot flashing unlock before flashing and fastboot flashing lock afterwards. The tool still validates that the bootloader is unlocked before proceeding.

Flash a specific version

uv run grapheneos-flasher shiba --version 2026050900 --flash

Sideload an OTA update (updates an existing GrapheneOS install, preserves data)

uv run grapheneos-flasher shiba --sideload

Downloads only the OTA update package (not the full factory image), then guides you through booting into recovery and sideloading via adb sideload. Use this to update a device already running GrapheneOS — it is not a substitute for a fresh flash.

Re-running without re-downloading

By default, files are saved in your current working directory. Running the same command again will skip files that are already present:

  ✓  shiba-install-2026050900.zip  (1573 MB)  (already exists, skipping)

Use --work-dir to specify a different location:

uv run grapheneos-flasher shiba --work-dir ~/grapheneos-files

If the directory does not exist the tool falls back to a system temp directory.

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Supported devices

Codename	Device
frankel	Pixel 10
blazer	Pixel 10 Pro
mustang	Pixel 10 Pro XL
rango	Pixel 10 Pro Fold
stallion	Pixel 10a
tokay	Pixel 9
caiman	Pixel 9 Pro
komodo	Pixel 9 Pro XL
comet	Pixel 9 Pro Fold
tegu	Pixel 9a
shiba	Pixel 8
husky	Pixel 8 Pro
akita	Pixel 8a
felix	Pixel Fold
tangorpro	Pixel Tablet
panther	Pixel 7
cheetah	Pixel 7 Pro
lynx	Pixel 7a
oriole	Pixel 6
raven	Pixel 6 Pro
bluejay	Pixel 6a

Devices are modelled by the Device enum in cli.py — member name is the codename, value is the display name. Device.from_codename(s) returns the member or None for unknown inputs.

For the authoritative list see grapheneos.org/faq#device-support.

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What the tool does

Fresh install (--flash)

1. Download allowed_signers, the factory image zip, and its .sig signature file from releases.grapheneos.org. Skips files already present in the working directory.
2. Verify the signature with ssh-keygen -Y verify, exactly as the official guide prescribes.
3. Extract the archive with tar xf.
4. Pre-flight checklist — pauses and shows what to prepare on your device before you type yes.
5. Unlock — checks fastboot getvar unlocked. If locked, sends fastboot flashing unlock, waits for the device to wipe and reboot back into fastboot, and verifies the new state. Skipped with --no-bootloader-mgmt.
6. Flash — runs bash flash-all.sh from inside the extracted directory.
7. Lock — sends fastboot flashing lock and verifies the bootloader is locked before the device reboots into GrapheneOS setup. Skipped with --no-bootloader-mgmt (reminder shown instead).

OTA sideload (--sideload)

1. Downloads only the OTA update package (no factory image).
2. Guides you through booting into recovery mode and selecting Apply update from ADB.
3. Runs adb sideload <ota.zip>.

Note: Sideloading is for updating a device already running GrapheneOS. For a fresh install, use --flash instead.

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Security

• Signature verification uses the same ssh-keygen -Y verify command as the official GrapheneOS CLI guide — no third-party crypto libraries.
• The tool refuses to flash if verification fails.
• All files are downloaded to the working directory (default: CWD).
• The factory image namespace is "factory images" and the identity is [e-mail], matching GrapheneOS's published signing policy.

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Architecture

Module	Class	Responsibility
ui.py	Instructions	Terminal output helpers (ok, fail, info, warn, block, step) and all user-facing instruction text
core.py	GrapheneOSFlasher	Top-level orchestrator
core.py	DownloadConfig	URL and filename construction
core.py	DefaultFileHandler	HTTP downloads and archive extraction
core.py	SecurityVerifier	ssh-keygen signature verification
core.py	DeviceManager	fastboot and adb device interaction, bootloader management
cli.py	—	Argument parsing and entry point

FileHandler is an abstract base class — supply a custom implementation to GrapheneOSFlasher(config, file_handler=...) for testing or alternative download strategies.

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Development

# Install dev dependencies
uv sync

# Run tests
uv run python -m pytest

# Run a specific test file
uv run python -m pytest tests/test_ui.py
uv run python -m pytest tests/test_core.py
uv run python -m pytest tests/test_cli.py

# With coverage
uv run python -m pytest --cov=grapheneos_flasher --cov-report=html

# Type checking
uv run mypy grapheneos_flasher

# Formatting and linting
uv run black grapheneos_flasher tests
uv run isort grapheneos_flasher tests
uv run flake8 grapheneos_flasher tests

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License

MIT. Provided for educational and personal use. Always verify the security of any flashing process against the official GrapheneOS documentation.