How to unlock the Samsung Galaxy S4 bootloader

Earlier this year, Android developers confirmed that AT&T began locking their Samsung Galaxy S4 bootloader. There are already mobile operators who have reputation locking down all their devices. Unfortunately, this can become a worldwide norm in the near future, which is bad news for those of you who enjoy to flash custom ROMs and kernels. Luckily for you, XDA Developers team are working hard to give you the possibility to unlock those non-unlockable bootloaders. There is a tool named CASUAL and with its help we are now going to unlock your Galaxy S4 bootloader.

To cut it short, Casual is a simple app that unlocks your device’s bootloader, roots it and installs TWRP recovery.

Note! Casual was only tested on Windows and Linux, thus we do NOT have confirmation whether it works on OS X powered machines or not. We don’t take responsibility for what’s done to your device. Please follow the below steps accurately.

 

Prerequisites

1. Casual crucially requires the latest Java installed on your computer. If you don’t have it, go ahead and install it now. In case you have it already, make sure it’s the latest version.
2. Download the latest available Casual tool.
   
3. Make sure you have the USB driver installed on your computer. If not, visit Samsung’s Developers page and download it.
4. Enable USB debugging on your device. To do that, go to Settings > Applications > Development > USB debugging.
5. Check to have an internet connection during the whole process, as CASUAL will download some files on the way.
6. Fully backup your phone. This process will wipe all data on it.

Note! If you’re on Windows 8, you have to install Download Mode drivers first. See this post on how to do it.

 

Unlocking Galaxy S4’s bootloader

1. Launch the .jar file you’ve downloaded earlier.
2. When opened, connect your device to computer via a USB cable.
3. Casual should show “Device Connected”. At this step click the “Do it” button.
4. As the tool runs its script you will see a warning message. Click on “Continue”.

And this is it. When Casual is done, your device will be rooted, with an unlocked bootloader and with TWRP recovery installed too. You can now proceed to install your desired CM. Check out our earlier posted tutorial on how to do that.