Unlocking Bootloader SE W8/X8 :
Before I start I must emphasise the fact that meddling with the bootloader is highly dangerous and will result in a hard brick if you don't follow proper instructions. Then, you will have to go and repair your phone by sending it to SE 
. I am not responsible if your phone dies on you because you didn't follow instructions or you screwed up somehow. I must also mention that this will probably void your warranty (rooting already probably voided it though) and that there is NO WAY to relock bootloader as of now.
Requirements: Rooted phone, Sony Ericsson PC Companion installed in PC, Courage ..
You do not need to have a sim lock on your phone to unlock your bootloader.
Recommended: Disable your antivirus (it might find a "virus" in ADB.exe even though there isn't one and might even interfere in bootloader unlocking process)
Note: Unlocking the bootloader of your phone will restore the original sim lock of your phone (if you had any) unless if you unlocked with EMMA/IMEI unlock code or it was factory-unlocked or if SE unlocked it!!
1. Download the files needed for the unlock. (Credits go to the_laser for this tool.)
Files needed to determine if unlocking your phone's bootloader is safe: (Credits also go to the_laser for this tool.)
1a. Download Flashtool from the below link :
Download and install Flashtool v0.5.3 here
Original Post : Flashtool.exe (Credits go to Androxyde and Bin4ry for this tool.)
After installing it, open the flashtool folder and open the drivers folder inside that. Double click on the ggsetup-2.2.0.11.exe file inside and install Gordon's Gate.
Note: This Gordon's Gate Driver Installation will work for X8, X10 mini and X10 mini pro. I'm not sure about that of W8 but I think that is also supported.
Then restart your computer.
Open task manager and kill any ADB.exe process you find in there and don't load Flashtool for the rest of the installation process.
download and install Sony Ericsson PC Companion from here (needed for the bootloader unlocking process)..
Unzip the files needed for bootloader unlocking (S1tool and Bootloader Unlock tool) into an appropiate location on your PC.
Note: Disable ur antivirus because it will say ADB.exe as virus but ADB.exe is not an virus ....
* Now turn off your phone.
* Open the directory you unzipped S1tool to and run S1tool.exe. Then, click on IDENTIFY button before proceeding to the next step .
* Boot your phone into flash mode (make sure you installed Gordon's Gate found in step 1a first). All users, press and hold back button while connecting cable from PC to phone. Continue holding back button until you get some output. Flash mode means ur mob LED should be in green colour ...
Example of output:
9/9/2011 21:41:44 Welcome to S1 identify tool
9/9/2011 21:45:13
9/9/2011 21:45:13 TO CONNECT NEXT PHONES
9/9/2011 21:45:13 X10 Xperia,E10 Xperia Mini,E15 Xperia X8,U20 Xperia Mini Pro
9/9/2011 21:45:13 LT15 Xperia ARC,MT15 Xperia NEO,R800 Xperia PLAY
9/9/2011 21:45:13 PRESS AND HOLD "BACK" BUTTON...
9/9/2011 21:45:13
9/9/2011 21:45:13 PLEASE ATTACH TURNED OFF PHONE NOW
9/9/2011 21:45:13
9/9/2011 21:45:46
9/9/2011 21:45:46 RUNNING S1_EROM VER "r8A029"
9/9/2011 21:45:46 SOFTWARE AID: 0001
9/9/2011 21:45:46 LOADER AID: 0001
9/9/2011 21:45:49 FLASH ID: "002C/00BC"
9/9/2011 21:45:49 LOADER VERSION: "R4A045"
9/9/2011 21:45:49
9/9/2011 21:45:49 MODEL (from GDFS): X8
9/9/2011 21:45:49 SOFTWARE VERSION: 1236-9291_2.1.1.A.0.6
9/9/2011 21:45:49 CUSTOM VERSION: 1241-3178_R1B
9/9/2011 21:45:49 FILESYSTEM VERSION: WORLD-1-8_2.1.1.A.0.6
9/9/2011 21:45:49 SERIAL NO: CB511SPH7Q
9/9/2011 21:45:49
9/9/2011 21:45:49 SEMC SIMLOCK CERTIFICATE
9/9/2011 21:45:49 Elapsed:36 secs.
If the simlock certificate specified is SEMC SIMLOCK CERTIFICATE, or anything other than NOT RECOGNIZED SIMLOCK CERTIFICATE, or if you are sure you sim-unlocked your phone using Omnius, jump to step 3.
If the simlock certificate specified is NOT RECOGNIZED SIMLOCK CERTIFICATE, you can't unlock the bootloader of your phone. If you try, radio capability of your phone will be disabled (this has been reported to be untrue by a number of people who claim to have unlocked bootloader successfully with msm7227_semc.cmd).
Do note that the SIMLOCK certificate doesn't mean that you have/don't have a sim lock on your phone.
3. Disconnect your phone from the computer, boot it up, and then reconnect your phone to your computer.
4. Enable USB debugging on your phone.
Note: Don't run Flashtool and terminate any ADB.exe process you find in task manager before performing step 5.
5. If you had
1: the SEMC SIMLOCK CERTFICATE message or if you
2: unlocked your phone using EMMA/IMEI code
3: or if your phone was already unlocked when you bought it (first-hand phone)
4: or if your phone is sim-locked, or if...
NOT CONFIRMED, TRY AT OWN RISK!
5: your phone was sim-unlocked through a 3rd party PC application (which was not Omnius) and was not SETool2,
THEN
run msm7227_semc.cmd in the directory you unzipped the unlocking files to and press any key to start the unlocking process. Alternatively, you could use Flashtool v0.5.3 to bootloader-unlock your phone (if you want to use Flashtool, go to step 5c). Go to step 5b2.
If you
1: didn't have the SEMC SIMLOCK CERTIFICATE message and didn't have the NOT RECOGNISED SIMLOCK CERTIFICATE message
2: or if you sim-unlocked your phone using SEtool2,
THEN
go to step 5a.[/U][/B]
5a. Run msm7227_Setool2.cmd in the directory you extracted the bootloader unlock tool to and press any key to start the process. Alternatively, you could use Flashtool v0.5.3 to bootloader-unlock your phone (if you want to use Flashtool, go to step 5c)
If you
1: know that your phone was sim-unlocked using Omnius,
THEN
go to step 5b1.
5b1. Run msm7227_OmniusSL.cmd in the directory you extracted the bootloader unlock tool to and press any key to start the process. Alternatively, you could use Flashtool v0.5.3 to bootloader-unlock your phone (if you want Flashtool, go to step 5c).
5b2. Open the example log included in the files. Wait 5 minutes. Then, compare the text in the window to those in the example log. They should be similar. Also, the last message on the window should be Press any key to continue. Note: It is recommended to turn off your antivirus before starting this as antivirus might interfere with the unlocking of bootloader on your phone (some antivirus software claim that there is virus in ADB.exe even though there isn't one)
Text in example log:
Code:
process requires standard 2.x android firmware.
Press any key to continue . . .
Getting ROOT rights.
1743 KB/s (585731 bytes in 0.328s)
error: protocol fault (no status)
Waiting ...
Removing NAND MPU restrictions via SEMC backdoor. Permanent. Require ROOT rights.
192 KB/s (3087 bytes in 0.015s)
success
Waiting ...
Getting ROOT rights.
Waiting ...
Writing patched semcboot. Two step process
First, we need get access to semcboot area
504 KB/s (8064 bytes in 0.015s)
Second, we need to write semcboot ;)
1130 KB/s (596916 bytes in 0.515s)
successfully wrote 0003ff00
Press any key to continue . . .
Note: If your log is very different from this please check if your bootloader is unlocked using step 7. If it is not unlocked, turn off your antivirus and repeat step 5 again. If you get some "error: protocol fault" messages, that is completely fine, this is because the "problem" is that your phone was still rebooting and USB debugging mode is not turned on when rebooting so it couldn't acquire the status and had an error. If you get many "Access is denied" messages, turn off your antivirus and try again. Some users reported that the "Access is denied" messages were eradicated and they successfully unlocked their bootloaders after turning off their antivirus.
5c.
Start Flashtool, connect your phone and then wait for your phone to be recognized.
Then, go to: Plugins/(insert device name here) Unlock/run
A screen will pop up and ask you to connect your phone in Flash mode
1. Unplug the USB cable from your phone.
2. Turn off your phone.
3. Press and hold the "Back" button on your phone.
4. Plug in the USB cable to your phone.
5. Release the "Back" button after the screen that popped up disappears.
The unlocking process will start.
Wait until Flashtool asks you to disconnect the cable off the phone, then turn on the device and connect the usb cable once again.
Wait for Flashtool to push the required files to your phone.
After a while, Flashtool will have the message "Successfully applied unlock" and the phone will reboot.
__________________________________________________ ____________
6. Disconnect your phone from the PC. Congratulations, your phone has an unlocked bootloader now!
7. To verify if your bootloader is unlocked successfully, again, use S1tool found here:
Also, download and install Flashtool v0.5.3 here (follow instructions on the website)
(Credits go to Androxyde and Bin4ry for this tool.)
After installing it, open the flashtool folder and open the drivers folder inside that. Double click on the ggsetup-2.2.0.11.exe file inside and install Gordon's Gate (needed for S1tool to work).
Note: This Gordon's Gate Driver Installation will work for X8, X10 mini and X10 mini pro. I'm not sure about that of W8 but I think that is also supported.
After downloading s1tool and extracting it to an appropiate location on your PC (not needed you already have S1tool), shut down your phone.
Open s1tool.exe found in the directory you extracted s1tool to and then click IDENTIFY button.
Boot your phone into flash mode (Press and hold back button while connecting it to your PC using an usb cable. The LED on your phone should flash green). Continue holding back button until you get some output.
Example of output:
Code:
9/9/2011 21:41:44 Welcome to S1 identify tool
9/9/2011 21:45:13
9/9/2011 21:45:13 TO CONNECT NEXT PHONES
9/9/2011 21:45:13 X10 Xperia,E10 Xperia Mini,E15 Xperia X8,U20 Xperia Mini Pro
9/9/2011 21:45:13 LT15 Xperia ARC,MT15 Xperia NEO,R800 Xperia PLAY
9/9/2011 21:45:13 PRESS AND HOLD "BACK" BUTTON...
9/9/2011 21:45:13
9/9/2011 21:45:13 PLEASE ATTACH TURNED OFF PHONE NOW
9/9/2011 21:45:13
9/9/2011 21:45:46
9/9/2011 21:45:46 RUNNING S1_EROM VER "r8A029"
9/9/2011 21:45:46 SOFTWARE AID: 0001
9/9/2011 21:45:46 LOADER AID: 0001
9/9/2011 21:45:49 FLASH ID: "002C/00BC"
9/9/2011 21:45:49 LOADER VERSION: "R4A045"
9/9/2011 21:45:49
9/9/2011 21:45:49 MODEL (from GDFS): X8
9/9/2011 21:45:49 SOFTWARE VERSION: 1236-9291_2.1.1.A.0.6
9/9/2011 21:45:49 CUSTOM VERSION: 1241-3178_R1B
9/9/2011 21:45:49 FILESYSTEM VERSION: WORLD-1-8_2.1.1.A.0.6
9/9/2011 21:45:49 SERIAL NO: CB511SPH7Q
9/9/2011 21:45:49
9/9/2011 21:45:49 SEMC SIMLOCK CERTIFICATE
9/9/2011 21:45:49 Elapsed:36 secs.
Note: The value of the "$" is dependent on an unknown factor. The unknown factor doesn't matter to us.
