You don't need to worry if the new firmware can be rooted or not as with unlocked bootloader you can always ROOT your device.
SE/Sony gives sneak-peaks/preview builds of latest OS which requires unlocked bootloaders, as they did with Xperia 2011 line (they had ICS alpha/beta), so who knows may be SE/Sony may give early builds of ICS (JellyBean???)
Most of this is taken from lollylost100's his tutorial from ARC thread (all credits for that concise tutorial go to him, i have elaborated on a few things and added device specific changes)
[ Before we begin unlocking bootloader ]
Get the IMEI code for your device: type *#06# in phone dialer to find it out, note only the digits (no dashes)
Make sure u have a windows PC with USB cable to connect the phone
Power down your phone and keeping the Volume Up button pressed connect the USB cable to PC this will trigger FASTBOOT mode and windows will start driver installation, extract the above package and point the driver install to that location (usb_driver) folder
Once drivers are installed just disconnect cable and power on device
At the bottom click 'Start Unlocking the Bootloader'
Quote:
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 phone dial pad and enter *#*#7378423#*#* to access the service menu.
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.
After you have verified that you can unlock bootloader, scroll to the bottom of the page and click "Continue"
You will get "Are you sure prompt" accept it by clicking "yes i am sure" (i assume that you have read an understood it)
Then accept the "legal terms"
Finally you will get a "Create Unlock request" page, enter your IMEI (sometimes the last digit needs to be removed for this to work), name and email address
You should now receive your unique unlock key, its displayed on screen, SAVE THIS KEY SAFELY
Extract fastboot_with_Android_USB_file.rar and open fastboot folder
Hold SHIFT and right click on the background of the folder
Select 'Open command window here'
Connect your phone in fastboot mode (turn phone off, hold Volume UP button and plug in USB Cable) [make sure drivers are installed as explained above)
In the cmd windows type in fastboot.exe -i 0x0fce getvar version
If a value is returned (it will return 0.5), it means the phone is correctly connected
Type in fastboot.exe -i 0x0fce oem unlock 0xKEY and replace KEY with the key which you received earlier.
Current Phones/Tablets:
Lumia 920 // Xperia Z // Xperia TL // Xperia ion // Xperia P // iPad 3 // Surface Pro Accessories
Sony Smartwatch // Sony Smart Wireless Headset pro // Sony LiveDock™ // Xperia ion Smartdock Past Phones/Tablets:
iPhone 1st Gen/3GS/4S // Nexus One // Dell Streak // Atrix 4g // Xperia Play // Lumia 900 // Xperia S // iPad 1
Click here for my Xperia firmware downloads.
Use the Thanks button if I helped.
Flash this FTF via FlashTool:
When it says enter flashmode, power down device and keeping VOLUME DOWN button pressed connect usb cable to phone, the device will now enter flashmode (green LED)
After this file is flashed reboot phone
Bootloader will now be relocked!!!
Incase device doesn't boot DO NOT PANIC... You can flash stock firmware FTF anytime to get back to stock ROM
P.S.: there is no official way to relock bootloader
Current Phones/Tablets:
Lumia 920 // Xperia Z // Xperia TL // Xperia ion // Xperia P // iPad 3 // Surface Pro Accessories
Sony Smartwatch // Sony Smart Wireless Headset pro // Sony LiveDock™ // Xperia ion Smartdock Past Phones/Tablets:
iPhone 1st Gen/3GS/4S // Nexus One // Dell Streak // Atrix 4g // Xperia Play // Lumia 900 // Xperia S // iPad 1
Click here for my Xperia firmware downloads.
Use the Thanks button if I helped.
So because my phone says I can't unlock the bootloader, does that mean I can never unlock the bootloader? Or do I have to wait to be able to root it first?
PS: I got my ion from Best Buy so is that why? Will I ever be able to unlock the BL ? I've rooted and unlocked my x10, back in the old days lol but I'm just wondering if there's any difference with getting a phone from at&t directly or from the sony store and best buy.
So because my phone says I can't unlock the bootloader, does that mean I can never unlock the bootloader? Or do I have to wait to be able to root it first?
Have to wait to see if another way to unlock the bootloader is discovered. Root and unlocking the bootloader are two different things that accomplish or allow different things you can do on the phone.
IE rooting allows you to uninstall system apps & bloatware, backup apps/data, make changes to build.prop etc. Unlocking the bootloader will give you access to fastboot so you can flash custom roms/kernels and other images such as a pre-rooted system image to gain root.
Current Phones/Tablets:
Lumia 920 // Xperia Z // Xperia TL // Xperia ion // Xperia P // iPad 3 // Surface Pro Accessories
Sony Smartwatch // Sony Smart Wireless Headset pro // Sony LiveDock™ // Xperia ion Smartdock Past Phones/Tablets:
iPhone 1st Gen/3GS/4S // Nexus One // Dell Streak // Atrix 4g // Xperia Play // Lumia 900 // Xperia S // iPad 1
Click here for my Xperia firmware downloads.
Use the Thanks button if I helped.
I wonder. If we can not unlock the bootloader for some LT28at, why is there a key to unlock it? I did the Sony bootloader unlock for fun and apparently they have a key for my LT28at even though it says bootloader unlock is not allowed.
I wonder. If we can not unlock the bootloader for some LT28at, why is there a key to unlock it? I did the Sony bootloader unlock for fun and apparently they have a key for my LT28at even though it says bootloader unlock is not allowed.
You can unlock bootloader on the LT28i and, accordingly, there is a file to be relock bootloader LT28i
You can unlock bootloader on the LT28i and, accordingly, there is a file to be relock bootloader LT28i
I understand that works for lt28i but I'm referring to lt28at the us model of the ion and why there is a bootlloader unlock code when we can't unlock it.
tried to unlock it via the sony site and if you did and it was successful have you tried to relock it using the file linked above? Would be nice to know if that works.
Current Phones/Tablets:
Lumia 920 // Xperia Z // Xperia TL // Xperia ion // Xperia P // iPad 3 // Surface Pro Accessories
Sony Smartwatch // Sony Smart Wireless Headset pro // Sony LiveDock™ // Xperia ion Smartdock Past Phones/Tablets:
iPhone 1st Gen/3GS/4S // Nexus One // Dell Streak // Atrix 4g // Xperia Play // Lumia 900 // Xperia S // iPad 1
Click here for my Xperia firmware downloads.
Use the Thanks button if I helped.
If the LT28i can be unlocked, what if we flash the international firmware on our LT28at's and then do the LT28i method? Maybe a stupid question but this is the first phone I've had that's a challenge to do stuff like unlocking and rooting. My last phone (HTC Aria) was extremely easy.
XDA Developer TV Producer Kevin set up his phone to respond to … more
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?