His translation is unlocking the boot loader and I have explained in another post it means.

The open developer community is important to Sony, so they have made it possible to unlock the boot loader for the launch of Xperia ™ certain devices from 2011 onwards. To find out which models are compatible with this service, please see the Supported Phones page to the left.

Please note that void the warranty of your device and / or any warranty from your operator if you unlock the bootloader. See warranty statement for your device for more information. In addition, due to the modification of device software, the Sony network repair is likely to have to replace key components before testing properly, repair and verify the device using our tools and software repair. Consequently, if Sony makes a warranty repair, Sony will probably be charged a service fee significant additional costs caused by the modification of the software.

Some of the contents of your device also may be inaccessible due to the elimination of DRM and security key user data partition safe to unlock the bootloader. We advise you to create backups as user data, settings and accounts are deleted. For Xperia ™ devices published 2013 or later (for example Xperia ™ Xperia ™ Z and ZL), the SD card from your device will be formatted and you will lose all content (eg, photos, music, videos) to unlock the manager boot.

If you are fully aware of the risks involved, and have a thorough knowledge about these technologies, go to bootloader unlocking instructions page. You should be aware that unlocking the bootloader will not give root access. The only way to get root access is a flash custom ROM with root access.

Instructions

First, you should confirm that it is possible to unlock the boot loader of your phone by dialing the service menu. On your phone, open the dialer and enter * # * # 7378423 # * # * to access the service menu.

1. On the phone, press Info Service> Configuration> Rooting Status. If Bootloader unlock allowed says Yes, then you can proceed to the next step. If you say no, or if the state is not present, the device can not be unlocked.

2. On the computer, click Continue at the bottom of this page to start the boot loader unlocking process.

3. Read the information in the popup and click Yes, I'm sure, if you're still sure you want to unlock the bootloader.

4. Read and accept the legal terms. Click I accept.

5. Enter your name, a valid email address and the first 14 digits of the IMEI or MEID number (clear the last digit if necessary). Click Submit. You can view the IMEI or MEID number by entering * # 06 # on your phone.

6. The boot boot loader unlock key will be sent to your email. Save it for later use.

7. Download and install the latest version of Android SDK developer.android.com.

8. Download and unzip the file. This is the standard android_winusb.inf-file with a few lines of code added to enable Fastboot to support Sony and Sony Ericsson. Make sure you are running Google USB Driver package version 4 or higher on your Android SDK. You can see current Google USB Driver package revision in the SDK Manager.

9. Place the unzipped file in the folder USB_Driver, located in the Android SDK> extras> google folder on your computer. OK to replace the old android_winusb.inf-file with the new file. If you can not find the folder USB_Driver, install the Google USB Driver Packager using the Android SDK Manager.

10. Turn off the phone.

11. On your phone, press and hold the Fastboot button while connecting the phone to the computer with a USB cable. Fastboot button may differ between different phone models. See page Fastboot button for more information on using the button on your phone.

12. On the computer, you are prompted to drivers. Select the folder where you placed the USB_Driver android_winusb.inf-file, and select the Android Bootloader Interface-file.

13. Open a command window and navigate to the folder in the Android SDK tools.

14. Enter fastboot.exe-i 0x0fce getvar version, and verify that you get a response back (eg "0.3"). This means that your phone is connected properly.

15. Warning! If you perform this step jumps to the boot loader. This may void the warranty and / or any warranty from your operator. If you still want to unlock the boot loader of your phone, enter fastboot.exe-i 0x0fce oem unlock 0xKEY, where key is the key to unlocking bootloader you have at the beginning of this instruction. The boot loader should now be successfully unlocked.

Now begin to unlock the boot loader of your phone. This way you can void the phone's warranty. Sony can not guarantee full functionality of your phone, and will not be responsible for any malfunction of the phone, or property damage or personal injury caused by the phone.

Are you sure you want to continue?
Create bootloader unlock key request
To create an application, enter your name, IMEI (or MEID) and a valid email address.
You will then get the boot loader unlock key by email. You can view the IMEI (or MEID) number by entering * # 06 # on your phone.

Clic here to enter your details and get the unlock code:
Are you really sure? | Sony Xperia

Please note! It will only be possible to unlock the boot loader for the launch of some of the following models of phones.

Sony Ericsson Xperia™ PLAY
Sony Ericsson Xperia™ arc
Sony Ericsson Xperia™ arc S
Sony Ericsson Xperia™ neo
Sony Ericsson Xperia™ neo V
Sony Ericsson Xperia™ pro
Sony Ericsson Xperia™ mini
Sony Ericsson Xperia™ mini pro
Sony Ericsson Xperia™ ray
Sony Ericsson Xperia™ active
Sony Ericsson Live with Walkman™
Sony Xperia™ S
Sony Xperia™ P
Sony Xperia™ go
Sony Xperia™ U
Sony Xperia™ sola
Sony Xperia™ acro S
Sony Xperia™ ion
Sony Xperia™ miro
Sony Xperia™ tipo
Sony Xperia™ tipo dual
Sony Xperia™ V
Sony Xperia™ J
Sony Xperia™ T
Sony Xperia™ TX
Sony Xperia™ E
Sony Xperia™ E dual
Sony Xperia™ ZL
Sony Xperia™ Z