Os dejo el registro de flashtool a ver si alguien me ilumina. Creo que puede tener algo que ver con drivers...
09/037/2013 15:37:17 - INFO - <- This level is successfully initialized
09/037/2013 15:37:18 - INFO - Flashtool Version 0.9.9.0 built on 2012-11-13 22:53:30
09/037/2013 15:37:18 - INFO - You can drag and drop ftf files here to start flashing them
09/037/2013 15:37:23 - INFO - Device disconnected
09/037/2013 15:37:55 - INFO - Device LT22 Exported successfully
09/038/2013 15:38:01 - INFO - Beginning import of LT22
09/038/2013 15:38:11 - INFO - Device LT22 imported successfully
09/038/2013 15:38:17 - INFO - Selected Sony Xperia P_6.1.1.b.1.75_Generic World.ftf
09/038/2013 15:38:17 - INFO - Preparing files for flashing
09/038/2013 15:38:25 - INFO - Please connect your device into flashmode.
09/038/2013 15:38:33 - INFO - Device connected in flash mode
09/038/2013 15:38:33 - INFO - Opening device for R/W
09/038/2013 15:38:33 - INFO - Start Flashing
09/038/2013 15:38:33 - INFO - Processing loader
09/038/2013 15:38:33 - INFO - Checking header
09/038/2013 15:38:33 - INFO - Ending flash session
09/038/2013 15:38:33 - ERROR -
09/038/2013 15:38:33 - ERROR - Error flashing. Aborted
09/038/2013 15:38:33 - INFO - Device connected in flash mode
09/039/2013 15:39:17 - INFO - Device disconnected