[Q] Unable to unlock bootloader

I just bought the phone which is UNBRANDED and check that the BOOTLOADER can be UNLOCKED under the configuration menu. The phone is rooted which I verified through a program. Using Android 4.4.2, Build 14.3.A.0.757.

Tried both the flashtools and the Sony official way with the unlock code.

Flashtools - gives me the error that the bootloader cannot be unlocked. Tells me to unplug the phone and turn it on.
Sony Official way - under the fastboot - it is confirmed the phone was connected but when I go to enter the code - it says failed <remote: command did not succeed.

I also look through other threads and tried adding a new folder under custom in flashtools with my serial number and unlock code from Sony. This did not work for me. I downloaded the latest adk, flashtools etc... with no luck.

Does anyone else have the same issues? I cannot find an answer in any forum. With a locked bootloader, I am limited to a few stock custom roms that doesn't require an unlocked bootloader.

coolkoushik07 said:

Plug ur phn in different usb port of computer

Click to expand...

Click to collapse

I tried that and it doesn't work.

I think I solve the issue. I went back to using flashtools.

My mistake was that I put the SERIAL folder in Custom folder. Instead, I have to put the SERIAL # folder in the MYDEVICE folder within the Custom directory. After I did that, I click on BLU and it gave the unlock screen with the phone IMEI number and unlock code given from Sony official bootloader unlock email. It says that it unlocked the bootloader.