How to Unlock the Bootloader on Your Softbank Xperia XZ1 (701SO): A Comprehensive Guide

Introduction: Understanding the Bootloader and Its Importance

The bootloader is a critical piece of software that runs before the operating system on your Xperia XZ1 (701SO). It’s responsible for initializing the hardware and loading the Android OS. Unlocking the bootloader grants you significantly more control over your device, allowing you to flash custom ROMs, install custom kernels, and gain root access. However, it’s crucial to understand the risks involved before proceeding, including voiding your warranty and potentially bricking your device if the process is not followed correctly. This guide will explore the possibilities, limitations, and alternatives for unlocking the bootloader and optimizing your Softbank Xperia XZ1 (701SO).

Checking Bootloader Unlock Status: Is Your Xperia XZ1 (701SO) Eligible?

Before attempting to unlock the bootloader, it’s vital to determine if your specific Xperia XZ1 (701SO) is even eligible. Softbank, like many carriers, often locks down the bootloader on the devices they sell, preventing users from unlocking it. This is a crucial step, as attempting to unlock a locked bootloader can lead to irreversible damage.

Using Service Menu Codes to Check Unlock Status

The easiest way to check your bootloader unlock status is using the service menu. Follow these steps:

1. Open the phone dialer.

2. Enter the code *#*#7378423#*#*. This will open the service menu.

3. Navigate to Service info > Configuration.

4. Look for “Rooting Status”.

   • If it says “Bootloader unlock allowed: Yes,” then you can proceed with the bootloader unlocking process.
   • If it says “Bootloader unlock allowed: No,” your device is likely locked by Softbank, and unlocking the bootloader through official means is not possible.

Understanding “Bootloader Unlock Allowed: No”

If you encounter “Bootloader unlock allowed: No,” it doesn’t necessarily mean all hope is lost. While official methods are blocked, alternative methods (which we will discuss later) might exist. However, these methods are often complex, risky, and may not be guaranteed to work. Thorough research and a deep understanding of Android device flashing are crucial before attempting any unofficial unlocking methods.

Official Method: Unlocking the Bootloader via Sony’s Website (If Allowed)

If your device is eligible for bootloader unlocking according to the service menu, you can proceed with the official method using Sony’s website. This method requires you to have the Android SDK platform tools installed on your computer, including ADB (Android Debug Bridge) and Fastboot.

Prerequisites for Official Unlock Method

• Android SDK Platform Tools: Download and install the Android SDK Platform Tools from the official Android Developer website. This provides the necessary ADB and Fastboot binaries. Ensure the ADB and Fastboot executables are added to your system’s PATH environment variable for easy access from the command line.
• Sony Xperia USB Drivers: Install the correct USB drivers for your Xperia XZ1 (701SO) on your computer. These drivers allow your computer to communicate with your phone in both ADB and Fastboot modes. You can usually find these drivers on Sony’s support website or by installing Sony PC Companion.
• Backup Your Data: Unlocking the bootloader will completely wipe all data from your phone. Ensure you have backed up all important data, including photos, videos, contacts, and documents, to a safe location (e.g., your computer or a cloud storage service).
• Sony Account: You will need a Sony account to obtain the unlock code.

Steps to Unlock the Bootloader (Official Method)

1. Enable Developer Options and USB Debugging: On your Xperia XZ1 (701SO), go to Settings > About phone and tap “Build number” seven times to enable Developer Options. Then, go to Settings > Developer options and enable “USB debugging” and “OEM unlocking” (if available).

2. Obtain Your IMEI Number: Dial *#06# on your phone to get your IMEI number. Write it down, as you will need it later.

3. Visit Sony’s Bootloader Unlock Website: Go to the official Sony bootloader unlock website and follow the instructions. You’ll need to select your device model (Xperia XZ1) and enter your IMEI number (without the last digit).

4. Receive Your Unlock Code: Sony will provide you with a unique unlock code. Keep this code safe.

5. Boot into Fastboot Mode: Power off your phone. Then, press and hold the Volume Up button while connecting your phone to your computer via USB cable. This will boot your phone into Fastboot mode.

6. Open a Command Prompt or Terminal: Open a command prompt or terminal window on your computer.

7. Execute the Fastboot Unlock Command: Navigate to the directory where you installed the Android SDK Platform Tools. Then, execute the following command:

   fastboot devices
   

   This command should list your device, confirming that it is properly connected in Fastboot mode. Next, execute the following command, replacing <UNLOCK_CODE> with the unlock code you received from Sony:

   fastboot oem unlock <UNLOCK_CODE>
   

8. Reboot Your Device: After the unlock command is successful, reboot your device. Your phone will now be unlocked.

Post-Unlock Considerations

• Factory Reset: Your phone will likely perform a factory reset after unlocking the bootloader.
• Warranty Void: Unlocking the bootloader will void your warranty with Sony and Softbank.
• DRM Keys: Unlocking the bootloader may also affect DRM keys, potentially impacting the functionality of certain apps and services that rely on DRM (Digital Rights Management).

Alternative Methods for Unlocking the Bootloader (Unofficial): Proceed with Extreme Caution

If the official method is not an option due to your device being locked by Softbank, there are alternative, unofficial methods that might work. However, these methods are highly risky and should only be attempted by experienced users who are comfortable with the potential for bricking their device. We strongly advise against attempting these methods unless you fully understand the risks involved.

Why Unofficial Methods are Risky

• Potential for Bricking: Incorrectly following unofficial methods can render your device completely unusable (bricked).
• Security Risks: Unofficial methods often involve using third-party tools and software, which may contain malware or compromise your device’s security.
• Lack of Support: You will likely receive no official support from Sony or Softbank if you encounter problems using unofficial methods.

Examples of Unofficial Methods (for informational purposes only - use at your own risk)

• Using Modified Fastboot Tools: Some developers have created modified Fastboot tools that attempt to bypass the bootloader lock. These tools often exploit vulnerabilities in older versions of Android.
• Exploiting EDL Mode (Emergency Download Mode): EDL mode is a low-level mode used for flashing firmware to devices. Some unofficial methods attempt to use EDL mode to unlock the bootloader. This process typically requires specialized hardware and software.
• JTAG Debugging: JTAG debugging is a hardware-based method that allows direct access to the device’s CPU. This method is extremely complex and requires specialized equipment and expertise.

Due to the inherent risks involved, we will not provide specific instructions for any unofficial bootloader unlocking methods. It is your responsibility to research and understand the risks before attempting any such method.

Rooting the Softbank Xperia XZ1 (701SO) Without Unlocking the Bootloader (If Unlock is Impossible)

If unlocking the bootloader is not possible, rooting your Xperia XZ1 (701SO) becomes more challenging but not necessarily impossible.

Utilizing Pre-Rooted ROMs (Custom ROMs):

Search online forums like XDA Developers for pre-rooted custom ROMs specifically built for the Xperia XZ1 (701SO) 701SO variant. These ROMs come with root access pre-installed, eliminating the need to unlock the bootloader. However, finding a compatible and stable ROM might be difficult.

Exploiting Vulnerabilities for Root Access (Advanced):

Certain vulnerabilities may exist in the device’s firmware that can be exploited to gain root access. Tools like Kingo Root, iRoot, or similar one-click root solutions might work, but success is not guaranteed, and they often come with security risks. Use them with extreme caution.

Using Magisk Manager for Rooting (Potential but unlikely without bootloader unlock):

In some rare cases, you might be able to patch the boot image of the stock ROM with Magisk Manager and flash it back to the device using ADB and Fastboot, even with a locked bootloader. This depends on whether the bootloader allows flashing of modified images.

Optimizing Your Xperia XZ1 (701SO) Without Root Access

Even without root access or bootloader unlocking, you can still optimize your Xperia XZ1 (701SO) for better performance and battery life.

Disabling Bloatware:

Many carriers and manufacturers pre-install apps (bloatware) that you may not need or use. You can disable these apps in Settings > Apps. Disabling apps prevents them from running in the background and consuming resources.

Managing App Permissions:

Review the permissions granted to your apps and revoke unnecessary permissions. This can improve privacy and security.

Using a Lightweight Launcher:

Replace the stock launcher with a lightweight alternative like Nova Launcher or Lawnchair Launcher. These launchers are designed to be fast and efficient.

Clearing Cache and Data:

Regularly clear the cache and data of apps you use frequently. This can free up storage space and improve performance.

Limiting Background Data Usage:

Restrict background data usage for apps that you don’t need to run in the background. This can save battery life and reduce data consumption.

Updating to the Latest Software:

Keep your phone’s software updated to the latest version. Software updates often include performance improvements and bug fixes.

Conclusion: Weighing the Risks and Rewards

Unlocking the bootloader on your Softbank Xperia XZ1 (701SO) can open up a world of possibilities, from installing custom ROMs to gaining root access. However, it also comes with significant risks, including voiding your warranty and potentially bricking your device. Before proceeding, carefully weigh the risks and rewards and ensure you have a thorough understanding of the process. If your device is locked by Softbank and the official unlock method is not available, consider the alternative optimization methods outlined above before attempting any risky unofficial unlocking methods. Remember, proceeding with caution and doing thorough research are crucial to successfully modifying your device. If you are successful, explore the vast Magisk Modules Repository hosted by Magisk Modules for additional tweaks and enhancements after gaining root access.