How To Root and Unlock Bootloader of Xperia Z (yuga)

HOW TO UNLOCK BOOTLOADER OF XPERIA Z

WARNING: The SD card of your device will be formatted and you will lose all content (for example photos, music, videos) when you unlock the boot loader

1. First, you should confirm that it is possible to unlock the boot loader of your phone by checking the service menu. In your phone, open the dialler and enter *#*#7378423#*#* to access the service menu.
2. In your phone, tap Service info > Configuration > Rooting Status. If Bootloader unlock allowed says Yes, then you can continue with the next step. If it says No, or if the status is missing, your device cannot be unlocked.
3. GO Here and click Yes, I am Sure.
4. Read through and accept the legal terms. Click I Accept.
5. Enter your name, a valid email adress and the first 14 digits of your phone’s IMEI or MEID number (remove the last digit if necessary). Click Submit. You can view the IMEI or MEID number by entering *#06# on your phone.
6. The unlock boot boot loader key will be sent to your email. Save it for later use.
7. Download and install the latest Android SDK from developer.android.com.
8. Download and unzip this 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 devices. Make sure you are running Google USB Driver package revision 4 or higher in your Android SDK. You can see current Google USB Driver package revision in the SDK Manager.
9. Place the unzipped file in the usb_driver folder, located in the Android SDK > extras > google folder on your computer. Accept to replace the old android_winusb.inf-file with the new file. If you can't find the usb_driver folder, please install the Google USB Driver Packager using the Android SDK manager.
10. Turn off your phone.
11. On your phone, push and hold the Volume up(+) button at the same time as you connect the phone to the computer with a USB-cable.
12. On your computer, you will be asked for drivers. Point to the usb_driver folder where you placed the android_winusb.inf-file, and select the Android Boot loader Interface-file.
13. Go to the tools folder within the Android SDK folder and Open a command window(press shift button and right click on the window and select Open Command Window here).
14. Enter fastboot.exe -i 0x0fce getvar version, and verify that you get a response back (for example "0.3"). This means your phone is connected properly.
15. Warning! If you perform this step, you will unlock the boot loader. This may void your 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 unlock boot loader key you got in the beginning of this instruction. The boot loader should now be successfully unlocked.

Now you can flash any custom ROMs/Kernel and you also dont need to worry if the new firmware can be rooted or not as with unlocked bootloader you can always ROOT your device

Sony gives sneak-peaks/preview builds of latest OS which requires unlocked bootloaders, as they did with Xperia 2011/2012 line, so who knows may be Sony may give early builds of next android OS..

HOW TO ROOT XPERIA Z?

Once the bootloader is unlocked its generally very easy to root but there were numerous issues where rooting wasnt working even using insecure kernel, so DooMLoRD, a Recognized Developer on XDA used the ramdisk of CF-Auto-Root for the Nexus 4, modified it a bit for working on the Xperia Z and thats it... Root achieved!

REQUIREMENTS:

• Firmware Version: 10.1.A.1.350
• Tested on C6603 and C6602
• Unlocked bootloader
• fastboot files here or here

DOWNLOADS:

• modified CF-Auto-Root kernel: 

Z_DooMLoRD_CF-Auto-Root-ported_FW-350.img

MD5HASH: a0c26a2b3dd9f2f174986d9ccddab40d

• Stock insecure kernel for FW (10.1.A.1.350): 

Z_DooMLoRD_insecure_FW-350.img

MD5HASH: c6a654e37cf6c5cc8e2d0c5fe2457d03

PROCEDURE:

1. Reboot into bootloader
2. Now in your PC go to the folder of fastboot files and place the downloaded img files there along with fastboot files.
3. Boot into fastboot (Volume Up + USB cable connected to PC)(BLUE LED will light up)
4. Now Open Command Prompt inside that folder using Shift+Right Click and type:"fastboot flash boot Z_DooMLoRD_CF-Auto-Root-ported_FW-350.img"
5. Reboot from fastboot "fastboot reboot"
6. The device will now start booting and u will get indication on screen saying (Device will reboot in 10 seconds) 
7. After CF-Auto-Root reboots device once, disconnect USB cable and do hard power off (3 vibrations)
8. [FYI: disconnect usb cable.. u have to do hard power off "press power button and keep VOLUME UP key pressed for 15 seconds"]
9. Connect device in fastboot mode and flash stock kernel "fastboot flash boot Z_DooMLoRD_insecure_FW-350.img"
10. Now reboot device and the device will start booting into OS "fastboot reboot"
11. You should now Download Busybox Installer from Market and install it at /system/xbin/
12. Thats it! device is now completely rooted!