Quiero comentarles que he seguido el tutorial de XDA:
[Tutorial] Relock bootloader! y este fue el resultado.
24/016/2013 23:16:16 - INFO - <- This level is successfully initialized
24/016/2013 23:16:17 - INFO - Flashtool Version 0.9.5.0 built on 2012-09-12 06:45:17
24/016/2013 23:16:17 - INFO - You can drag and drop ftf files here to start flashing them
24/016/2013 23:16:24 - INFO - Device disconnected
24/016/2013 23:16:35 - INFO - Selected Xperia_Relock_bootloader.ftf
24/016/2013 23:16:35 - INFO - Preparing files for flashing
24/016/2013 23:16:35 - INFO - Please connect your device into flashmode.
24/016/2013 23:16:48 - INFO - Device connected in flash mode
24/016/2013 23:16:48 - INFO - Opening device for R/W
24/016/2013 23:16:48 - INFO - Reading device information
24/016/2013 23:16:48 - INFO - Phone ready for flashmode operations.
24/016/2013 23:16:48 - INFO - Start Flashing
24/016/2013 23:16:48 - INFO - Processing loader
24/016/2013 23:16:48 - INFO - Checking header
24/016/2013 23:16:48 - INFO - Flashing data
24/016/2013 23:16:50 - INFO - Loader : S1_Loader_Root_773f - Version : R4A066 / Bootloader status : ROOTABLE
24/016/2013 23:16:50 - INFO - Flashing preset.ta
24/016/2013 23:16:50 - INFO - Writing TA unit : [00, 00, 08, B2, 00, 00, 00, 02, 00, 00]
24/016/2013 23:16:50 - INFO - Ending flash session
24/016/2013 23:16:50 - INFO - Flashing finished.
24/016/2013 23:16:50 - INFO - Please unplug and start your phone
24/016/2013 23:16:50 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings
24/016/2013 23:16:50 - INFO - Device connected in flash mode
Al terminar inicio el teléfono normalmente, mi duda es como puedo hacer que PC Company Sony me actualice el teléfono por OTA, Saludos.