Unable to unlock bootloader.

[DocRockulus]

I have an Xperia tablet Z, I've checked the service menu and confirmed that the bootloader unlock allowed value is "Yes".

I've requested and received the unlock key, and following the instructions on http://unlockbootloader.sonymobile.com/instructions.

I've prepared my computer for the process, and can confirm that the device connects to fastboot without issue.

Upon using the fastboot.exe -i 0x0fce oem unlock 0xXXXXXXXXXXXXXXX, I receive the following error:

...

FAILED (remote: Command did not succeed)
finished. total time: 0.035s

What do?

[DocRockulus]

I've also used the 3rd party utility "FlashTool" and am presented with a slightly more detailed error message indicating "Your phone bootloader cannot be officially unlocked". 

Once again, I can confirm that the "bootloader unlock allowed" status is "yes".

[Uliwooly]

Before you unlocked the bootloader, you are aware that you will void your warranty and there are other issues, an example, the Xperia Z1 if you unlock the bootloader the camera wont work at all 

[DocRockulus]

Yeah, I don't care about the warranty, I just need the bootloader unlocked so I can test my AOSP on xperia build.

[Ponns15]

 me pasa lo mismo con mi xperia z1 compact no se que hacer casi no hay apoyo en foros 😕