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Flashing Fastboot Packages

Device Compatibility Required

Fastboot packages can only be flashed on a limited set of devices. Not all Android devices support fastboot package flashing. Please read the device requirements section below carefully to ensure your device is compatible.

Device Requirements​

Supported Devices​

Fastboot package flashing is supported only on devices that meet ALL of the following criteria:

  • Android Version: Launched with Android 10 or later
  • Dynamic Partitions: Device must support Dynamic Partitions (super partition)
  • Fastbootd: Device must have fastbootd support (userspace fastboot)

These features typically became standard in devices released with Android 10+, but some older flagships may also support them.

Unsupported Devices​

The following device types are NOT compatible with fastboot package flashing:

  • Samsung devices - Samsung uses Odin protocol (proprietary download mode) and does not support fastboot packages
  • Older devices - Devices released before Android 10 without Dynamic Partitions support (even if the community has implemented a dynamic partition retrofit)
  • Devices without fastbootd - Devices that only support bootloader-level fastboot, not userspace fastboot
  • Some custom ROM implementations - Devices with custom bootloaders that don't implement fastbootd
Samsung Devices

If you own a Samsung device, do not attempt to use fastboot package flashing. Please refer to your device's specific installation method instead.

Understanding Fastboot Packages​

A fastboot package (often named with .zip extension) is a complete ROM package designed to be flashed through fastboot in a single operation. Unlike traditional ADB sideloading, fastboot packages:

  • Are flashed directly to partitions via fastboot protocol
  • Support flashing multiple partitions simultaneously
  • Require the device to be in fastbootd/userspace fastboot mode
  • Work with Dynamic Partition layouts
Availability

Fastboot packages are available since Halcyon 16.0 Bloom and later versions.

Prerequisites​

Remove Accounts and Lock Screen - CRITICAL

Before flashing, you MUST remove:

  • Your lock screen (PIN, pattern, password, fingerprint, face unlock)
  • All accounts (Google, Samsung, Xiaomi, etc.)

Failure to do so can:

  • Lock you out of your device via Factory Reset Protection (FRP), making it unusable
  • Permanently damage the TEE (Trusted Execution Environment) on some devices
  • Render biometric hardware (fingerprint sensor) permanently unusable on affected devices

This damage has been confirmed on multiple devices and cannot be repaired after flashing. This is not reversible.

Before flashing a fastboot package, ensure you have:

  • ADB/Fastboot tools installed on your computer
  • USB drivers installed (if on Windows)
  • Unlocked bootloader (device-dependent)
  • USB cable capable of data transfer (not just charging)
  • Removed all accounts and lock screen from your device

Installation Steps​

1. Enter Fastboot Mode​

The method varies by device. Common combinations include:

  • Power + Volume Down
  • Power + Volume Up
  • Power + Volume Down + Volume Up (press simultaneously)

Consult your specific device documentation for the exact key combination.

2. Connect to Computer​

Connect your device to your PC via USB cable and verify it's detected:

fastboot devices

You should see your device listed with a serial number.

Check Connection

If your device is not listed, check USB drivers and try a different USB port.

3. Wipe the Device​

Before flashing, wipe the device to ensure a clean installation:

fastboot -w

This command will erase all data on your device.

4. Flash the Package​

Download the fastboot package for your device and run:

fastboot update fastboot-halcyon_XXXXXX.zip

Example: fastboot-halcyon_surya-16.2-20260210-1800-Alpha-GMS-signed.zip

(Replace with your device's actual package filename)

This command will:

  • Extract all partitions from the package
  • Flash them to the appropriate partitions
  • Verify each partition after flashing
  • Automatically reboot when complete

5. Verify Installation​

After flashing completes and the device reboots:

fastboot reboot

Or allow the automatic reboot to proceed. Your device should boot into the newly flashed ROM.

Getting Help​

If you encounter issues not covered here:

  • Check your device-specific documentation
  • Ask in our Telegram group for community support
  • Verify you followed all prerequisites correctly
  • Provide your device codename and exact error message when asking for help
Need Device-Specific Help?

Each officially supported device has its own documentation page with device-specific instructions and troubleshooting. Refer to the Official Devices section for your device.