Fastboot remains an essential tool for Android enthusiasts, developers, and advanced users who want to customize, repair, or recover their devices. Whether you want to unlock your bootloader, flash custom ROMs, recoveries, or troubleshoot issues, mastering fastboot commands is crucial.

This guide provides a thorough overview of fastboot commands relevant to Android 10 and later versions, incorporating the latest features, security changes, and best practices.

What is Fastboot?

Fastboot is a protocol and tool integrated into the Android SDK Platform Tools that allows communication with your device over USB when it is in bootloader mode. It lets you flash system partitions, unlock bootloaders, reboot devices, and perform low-level operations without booting the full Android OS.

Unlike ADB (Android Debug Bridge), which requires the OS to be running or in recovery mode, fastboot works when the device is powered off or in bootloader mode.

Preparing to Use Fastboot

Before using fastboot commands, ensure the following:

• USB Debugging is enabled in Developer Options (for unlocking and flashing operations).
• You have installed the latest Android SDK Platform Tools on your PC.
• Your device’s bootloader is unlocked (some commands require unlocking).
• You have appropriate USB drivers installed (especially on Windows).
• A USB cable and a compatible PC (Windows, macOS, Linux).

To enter fastboot mode (bootloader):

• Power off your device.
• Use the device-specific key combo (commonly Volume Down + Power).
• Or, via ADB, use the command:
  adb reboot bootloader

Common Fastboot Commands (Android 10+)

Here are the essential fastboot commands you should know and how to use them in 2025:

1. Check Device Connection

fastboot devices

Lists devices connected in fastboot mode. Use this to verify your device is properly detected.

2. Reboot Commands

• Reboot to the system:

fastboot reboot

• Reboot to bootloader (fastboot mode):

fastboot reboot bootloader

• Reboot to recovery mode (if custom recovery installed):

fastboot reboot recovery

3. Unlock Bootloader

Unlocking the bootloader is often required before flashing custom ROMs or recoveries. Note: Unlocking usually erases all data and may void your warranty.

fastboot flashing unlock

On some devices, this triggers an on-screen confirmation prompt.

4. Lock Bootloader

To relock the bootloader (usually to restore warranty or for security):

fastboot flashing lock

5. Flash Images

Fastboot can flash partitions such as boot, recovery, system, vendor, and others.

• Flash a recovery image:

fastboot flash recovery recovery.img

• Flash boot image:

fastboot flash boot boot.img

• Flash system image:

fastboot flash system system.img

• Flash vendor image:

fastboot flash vendor vendor.img

• Flash userdata (wipe data partition):

fastboot flash userdata userdata.img

6. Erase Partitions

To erase specific partitions:

fastboot erase cache
fastboot erase userdata

Be cautious with erase commands; erasing userdata wipes your personal data.

7. Format Partitions

Formatting partitions is different from erasing as it prepares partitions for new data structures:

fastboot format userdata
fastboot format cache

8. OEM Commands

Some devices support OEM-specific commands for locking/unlocking or other manufacturer-specific operations.

• Example to check OEM lock status:

fastboot oem device-info

• Enable or disable OEM unlocking (varies by device):

fastboot oem unlock
fastboot oem lock

Note: On newer Android devices, fastboot flashing unlock is replacing many fastboot oem commands.

9. Get Partition Info

To list the current partitions and their sizes:

fastboot getvar all

Or

fastboot getvar partition-size:<partition-name>

10. Boot an Image Temporarily

To test a boot or recovery image without flashing:

fastboot boot boot.img

This boots the image temporarily until next reboot.

11. OEM Factory Reset

Some devices allow factory reset via fastboot OEM commands:

fastboot oem factory-reset

Check device-specific docs as support varies.

12. Update Firmware

Some manufacturers provide factory images with scripts to flash all partitions at once:

fastboot update image.zip

Or use flashing scripts provided with factory images.

Important Considerations for Android 10 and Above

Enhanced Security

• Starting with Android 10 and continuing with Android 11+, devices implement Verified Boot and AVB (Android Verified Boot), which enforce boot image and system integrity.
• After flashing partitions, you may need to flash vbmeta with --disable-verity or --disable-verification flags to avoid boot loops if modifying system images.

Example:

fastboot flash vbmeta --disable-verity --disable-verification vbmeta.img

• Be cautious with modifications on devices using dynamic partitions (introduced in Android 10+), as partitions like system and vendor may be merged or virtualized.

Dynamic Partitions and Super Images

• Android 10 introduced Dynamic Partitions, combining multiple partitions into a single “super” partition.
• Flashing system, vendor, or product images separately might require using fastboot flash super or using specialized commands.

Example:

fastboot flash super super.img

• Modifying dynamic partitions is more complex and usually requires using fastboot –slot commands to specify the active slot.

A/B Partition Devices

Many modern devices use A/B system updates, meaning they have two sets of partitions (slot A and slot B) to allow seamless updates.

• To check current active slot:

fastboot getvar current-slot

• To set active slot:

fastboot --set-active=a
fastboot --set-active=b

Flashing images to the inactive slot ensures safer updates.

How to Install Fastboot (Platform Tools) in 2025

• Download the latest Android SDK Platform Tools from the official Android developer website:
  https://developer.android.com/studio/releases/platform-tools
• Extract the tools and add the folder to your system’s PATH environment variable for easy command-line access.

Conclusion

Fastboot is an indispensable utility for Android power users in 2025, especially with evolving Android versions bringing new security features and partitioning schemes. Mastering these commands allows you to unlock bootloaders, flash custom ROMs, recover devices, and experiment safely.

Always double-check device-specific instructions, back up your data, and ensure you have the latest tools. With proper precautions, fastboot empowers you to take full control of your Android device.