How to Unlock Bootloader on Android Phones

If you are new to the world of Android hacking and rooting, then there are many geeky terms that might bamboozle you and might end you up with quitting the idea of rooting altogether. For latest technology followers Android OS don’t need introduction. Recent reports states that Android Operating System crossed the 79% of the smartphone market share. Android users are aware of word rooting and custom ROM flashing, but some Android devices needs to unlock Bootloader in order to proceed to next step. So what is Bootloader? How to unlock Bootloader? on Android Phones.

What is a Bootloader? 

In literal terms, bootloader is code that is executed before any Operating System starts to run. The concept of bootloaders is universal to virtually all Operating systems that inculcates operating systems on your PC, laptop, smartphones, and other such devices. Bootloaders basically package the instructions to boot operating system kernel and most of them also have their own debugging or modification environment. As the bootloader kicks off before any piece of software on your device, it makes it extremely processor specific and every motherboard has it’s own bootloader. This is one reason that all Android phones have different Custom ROMS developed due to high variance of processing hardware present on the device.

Why is Bootloader Locked?

A bootloader is usually locked on an Android device because although it’s an open source OS, still the manufacturers want you to stick to their Android OS version specifically designed for the device. In order to apply this concept, manufacturers lock the bootloader. With a locked bootloader on Android devices, it is virtually impossible to flash a Custom ROM and forced attempts void warranty as well as usually end up in bricks. Therefore, the first step is to always unlock the bootloader.
 

Android Bootloaders

Every Android phone has a bootloader that instructs the operating system kernel to boot normally. But you need to understand one thing here that as Android OS is an open source OS and is available on a variety of different hardware, every manufacturer has their own version of bootloader specific for the hardware present in it’s environment. We also saw couple of weeks back that Motorola packaged an “eFuse” command in their Android phones, which could brick (permanently turn off) your device in case you tried to flash a Custom ROM.

 

Why To Unlock Bootloader On Android Devices?

If you want root, you’d be wanting to flash Custom ROM post-root, and if you want to install a Custom ROM, you’d need to have your stock bootloader unlocked. In simple terms Unlocking the bootloader allows you to install custom Firmware on your Android phone.

How To Unlock Bootloader On Nexus Android Devices: 

Before attempting this guide to unlock your bootloader, please note that this is intended for Android phone with STOCK ANDROID OS ONLY. We will be using a Google Nexus One as our reference because it comes with zero user interface alteration from it’s manufacturer. If you are looking to unlock bootloaders on handsets which already have a custom UI from manufacturers installed like HTC Sense, Samsung TouchWiz etc, then this guide won’t be applicable.

1) The first step is download and install Android SDK as instructed in this post.

2) Once you are done with downloading and installing SDK, turn off your device and boot in bootloader mode:

• On Nexus One, press and hold the power button and trackball.
• On Nexus S, press and hold the volume-up and power buttons.
• On Galaxy Nexus, press and hold volume-up, volume-down and power buttons.

• On Nexus 4, press and hold volume-down and power buttons.

• On Nexus 7, press and hold volume-down and power buttons.
• On Nexus 10, press and hold volume-up, volume-down and power buttons.

3) Connect your device to your PC via USB and wait till any drivers are installed, which should happen automatically.
4) Now go to command prompt / terminal interface on your computer and type following command:

fastboot oem unlock

5) Once this is done, your phone will show a screen that will prompt you regarding unlocking bootloader. Read through the instructions carefully and confirm by pressing volume up button followed by the power button.

There you go! You now have your bootloader on your Nexus Android device unlocked.