The Complete Guide to Android Fastboot Commands

Chapter 1: What is Fastboot?

Fastboot is a direct booting protocol that allows direct access to an Android device's bootloader or recovery mode. It is commonly used for advanced operations like firmware updates, debugging, and bootloader unlocking on a device. Fastboot runs over a USB cable connected from a host computer to the device. Important: To use Fastboot commands, the device's bootloader must be unlocked or support Fastboot mode.

Advantages of Fastboot

Using Fastboot allows you to unlock an Android device's bootloader, making it possible to install custom ROMs, root the device, etc. It is also used when needing to recover a device.

Precautions When Using Fastboot

Care must be taken when using Fastboot commands. Entering incorrect commands can cause serious damage to a device. Therefore, you should always be sure of exactly what command you are using and what effect running that command will have.

Chapter 2: Basic Usage of Fastboot Commands

To use Fastboot commands, an Android device first needs to be booted into Fastboot mode. On most devices, holding down the power button and volume down button simultaneously will enter Fastboot mode.

Entering Fastboot Mode

The method for entering Fastboot mode varies by device, but is generally:

  
1. Completely power off the device.
2. Hold down power button and volume down button simultaneously. 
3. When 'Fastboot' appears on the screen, release buttons.

Running Fastboot Commands

To run Fastboot commands, first the Android SDK Platform-Tools must be installed on the computer. Then open a command prompt or terminal and enter 'fastboot' followed by the desired command.

Fastboot Command Example

fastboot devices 

The above command lists all devices connected in Fastboot mode.

Chapter 3: List and Detailed Descriptions of Fastboot Commands

Below is a list of Fastboot commands and descriptions of what each command does.

List of Fastboot Commands

1. fastboot devices: Lists all devices connected in Fastboot mode.
2. fastboot oem unlock: Unlocks device's bootloader.  
3. fastboot oem lock: Locks device's bootloader.
4. fastboot reboot: Reboots the device.  
5. fastboot flash: Flashes an image to a partition.
6. fastboot boot: Directly boots a kernel or RAM disk using the bootloader.  
7. fastboot erase: Erases a flash partition. 

Detailed Descriptions of Fastboot Commands

fastboot devices lists all devices connected in Fastboot mode. This checks that Fastboot has connected properly with the device.

fastboot oem unlock unlocks a device's bootloader. This makes it possible to install custom ROMs, root the device, etc.

fastboot oem lock locks the device bootloader again. This maintains security on the device.

fastboot reboot reboots the device.

fastboot flash flashes an image to a partition, allowing installation of a new operating system.

fastboot boot directly boots a kernel or RAM disk using the bootloader.

fastboot erase erases a flash partition, completely wiping data from the device.

Chapter 4: Precautions and Tips

Fastboot commands are very powerful so must be used with caution. Misusing them can cause serious damage to a device. Therefore you should always be sure of exactly what command you are using and what effect running that command will have.

Precautions

When using Fastboot commands always remember:

1. Fastboot commands can make serious changes so caution is necessary.
2. Always backup device data before running commands. 
3. The device bootloader must be unlocked to use Fastboot commands.

Tips

Tips that can help when using Fastboot commands:

 
1. When first using Fastboot, start with simple tasks like unlocking bootloader or rebooting device.
2. Always ensure steady power supply when using Fastboot.
3. Entering wrong Fastboot commands can seriously damage device so always input commands precisely.