How to unlock your bootloader without losing the DRM keys
Sony has designed this phone such that if you unlock your bootloader you lose your TA partition PERMANENTLY which includes some of the Xperia features and licenses that have to do with image processing etc. forever. You will also no longer receive OTAs. So in theory, without a copy of this TA partition (which is unique to each device and cannot be copied over from another) unlocking the bootloader results in an irreversible loss of some of your phone's features. Relocking the bootloader will not bring them back.
A hack exists that allows you to backup the TA partition before you unlock the bootloader. This backup will make the process completely reversible so if you ever need to send the tablet to Sony for repair or just want to return it to its original state you have a way. Follow these instructions carefully:
1.0- Before you begin keep in mind that this procedure, especially the unlocking step, completely erases your tablet. Disable myXperia and remove your google account before proceeding. The following will likely not work well with encryption.
1.1- Start by clean flashing any 28.0.A.8.266 firmware, For this tutorial I used the Customized NL ftf that you can get from here.
1.2- Enter service Mode by dialing *#*#7378423#*#* -> Service info -> configuration, and make sure the device is unlockable.
Also check -> Service Tests -> Security and you will see a bunch of "active" and "OK" attributes. You can take screenshots for your reference.
1.3- Turn on usb debugging mode on your phone.
1.4- Download iovyroot zip v0.4 or higher from here.
1.5- Unzip this zip file into a folder of your choice and open a command terminal there.
1.6- Connect the phone which is now in USB debugging mode to your PC and answer yes when the phone asks to authorize the PC to access it in USB debugging mode. You can check that the PC indeed sees the phone by running this command
1.9- Save this file in a very safe place. Save it on your hard disk, AND email it to yourself, AND put it on your google drive. If you lose this file you can never reverse the bootloader unlocking process.
1.10- Reboot the device.
1.11- Now you can unlock the bootloader. Follow the instructions at Sony's official website at http://developer.sonymobile.com/unlockbootloader Also save your unlock code that you obtain in this step somewhere. You may need it some day.
1.12- Reboot the device and it will briefly enter recovery and then start the phone initial setup.
1.13- (Optional) you can easily verify that your bootloader is unlocked by entering the fastboot mode, obtaining any boot image, and running the following command to boot your tablet with that image:
1.15- As a side effect of unlocking the bootloader you lose the ability to receive OTA updates. Clean flash a Marshmallow ftf to continue. For this tutorial I used Marshmallow 6.0 E6553_Customized HK_1294-9654_32.1.A.1.185_R7C (the latest firmware at the time of this writing.)
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Sony has designed this phone such that if you unlock your bootloader you lose your TA partition PERMANENTLY which includes some of the Xperia features and licenses that have to do with image processing etc. forever. You will also no longer receive OTAs. So in theory, without a copy of this TA partition (which is unique to each device and cannot be copied over from another) unlocking the bootloader results in an irreversible loss of some of your phone's features. Relocking the bootloader will not bring them back.
A hack exists that allows you to backup the TA partition before you unlock the bootloader. This backup will make the process completely reversible so if you ever need to send the tablet to Sony for repair or just want to return it to its original state you have a way. Follow these instructions carefully:
1.0- Before you begin keep in mind that this procedure, especially the unlocking step, completely erases your tablet. Disable myXperia and remove your google account before proceeding. The following will likely not work well with encryption.
1.1- Start by clean flashing any 28.0.A.8.266 firmware, For this tutorial I used the Customized NL ftf that you can get from here.
1.2- Enter service Mode by dialing *#*#7378423#*#* -> Service info -> configuration, and make sure the device is unlockable.
Also check -> Service Tests -> Security and you will see a bunch of "active" and "OK" attributes. You can take screenshots for your reference.
1.3- Turn on usb debugging mode on your phone.
1.4- Download iovyroot zip v0.4 or higher from here.
1.5- Unzip this zip file into a folder of your choice and open a command terminal there.
1.6- Connect the phone which is now in USB debugging mode to your PC and answer yes when the phone asks to authorize the PC to access it in USB debugging mode. You can check that the PC indeed sees the phone by running this command
1.7- Run the following command:
1.8- VERY IMPORTANT: Make sure the command completes with no errors. If all goes well you will have a file with a name like TA-05052016.img (the name may be different for you) with a size of 2MB in your folder.
1.9- Save this file in a very safe place. Save it on your hard disk, AND email it to yourself, AND put it on your google drive. If you lose this file you can never reverse the bootloader unlocking process.
1.10- Reboot the device.
1.11- Now you can unlock the bootloader. Follow the instructions at Sony's official website at http://developer.sonymobile.com/unlockbootloader Also save your unlock code that you obtain in this step somewhere. You may need it some day.
1.12- Reboot the device and it will briefly enter recovery and then start the phone initial setup.
1.13- (Optional) you can easily verify that your bootloader is unlocked by entering the fastboot mode, obtaining any boot image, and running the following command to boot your tablet with that image:
1.14- (Optional) you can see that the DRM keys are erased from your tablet by repeating step 1.2 but this time you will see a bunch of errors under Service Tests -> Security.
1.15- As a side effect of unlocking the bootloader you lose the ability to receive OTA updates. Clean flash a Marshmallow ftf to continue. For this tutorial I used Marshmallow 6.0 E6553_Customized HK_1294-9654_32.1.A.1.185_R7C (the latest firmware at the time of this writing.)
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