Unlocking your android smart phone to install custom ROM

Hello All,

In this post I am going to share the experience I had in unlocking the boot loader of my Nexus 7 2012 model tablet. The idea behind unlocking is to install custom ROM in it and explore the features offered by custom ROM. 
If you have any old smart phone or tablet which you are not using much or not using at all, then this idea might be of some interest to you too. 

There are certain things I would like to highlight in advance before we further discuss on the idea


1) Unlocking the boot loader will void the warranty of your phone or tablet. I suggest to try it out on any old phone or tablet which you are not using as daily driver because if something goes wrong then it requires additional efforts to make the device functional

2) Unlocking boot loader will erase your data ( factory data reset ). So better back up all the data if you are planning to try your hand on this

If you are fine with both the pointers mentioned above then you can give it a try

Unlocking the boot loader will give you more options to be carried on your device. In my case I am planning for installing Cyanogenmod on my device which has plenty of options to explore

Installing custom ROM in your smart phone or tablet will introduce new features which are not available in stock android or at least hidden from operation. If you like trying out new features in your smart phone or tablet, then you should definitely give it a try

I will share the steps which I followed to unlock the boot loader of Nexus 7 2012 version. I used system running Ubuntu 14.04 LTS version while doing the process. If you have a device which is not running stock android then the process might vary. The steps I have carried out can be tried out over Nexus devices

If you are using different OS then few steps might vary. If it is variant of linux, then the steps shouldn't vary much except installing the packages. For windows, you need to download android SDK and set up environment path for adb and fastboot

adb ( android debug bridge) and fastboot are tool kits used while unlocking the boot loader. To proceed further you need to give a read on them if you have not done already 

browse on the below wiki link to know more on adb and fastboot

http://en.wikipedia.org/wiki/Android_software_development#ADB

We need to install adb and fastboot packages in Ubuntu to proceed further. The same can be done by using the below commands in the terminal

sudo apt-get install android-tools-fastboot

sudo apt-get install android-tools-adb

once we have the fastboot and adb packages. we need to connect the phone/tablet into the system with the usb cable.

Before connecting phone/tablet to system, we need to make sure developer options is available by tapping 7 times on the build number (settings - about phone - build number)

Once we are done, developer options will be available under the settings page. Inside developer options, we need to grant permission for USB debugging

now run the below command in the terminal 

sudo adb reboot bootloader

We should be now seeing the actual boot loader screen in the phone/tablet. The same thing can be done by physical key combination but it varies from device to device

Now give the below command to check whether you are connecting to proper device

sudo fastboot devices

Your device serial number will be displayed in the screen. The same serial number can be seen in the boot loader screen

We are almost there. Give this last command to unlock your phone 

sudo fastboot oem unlock

Now you should get some disclaimer accepting which will unlock your phone. Hit the power button to accept the disclaimer( This can vary from device to device).Unlocking your phone will do factory data reset and as said before this will VOID your phone/tablet warranty

You can check whether you have successfully unlocked your phone in 2 ways

One you can see in  the fastboot mode, status will be displayed as unlocked.
Secondly  while booting up, an unlock symbol will appear in the splash screen.

Hope you succeeded in unlocking your phone, now you can install any Custom ROM into your phone and start exploring them.

Thanks for reading

Cheers!