[Sony Xperia T, TL, TX, V] jogai:
I think the drivers werent correctly installed, but it makes no difference:

20/013/2016 23:13:43 - INFO - Flashtool Version 0.9.22.3 built on 08-06-2016 22:30:00
20/013/2016 23:13:43 - INFO - Executing search strategies to find proxy selector
20/013/2016 23:13:43 - INFO - No proxy found for IE. Trying next one
20/013/2016 23:13:43 - INFO - Strategy firefox failed trying next one : No Firefox installation found
20/013/2016 23:13:43 - INFO - No proxy found for java. Trying next one
20/013/2016 23:13:43 - INFO - Syncing devices from github
20/013/2016 23:13:43 - INFO - Opening devices repository.
20/013/2016 23:13:43 - INFO - Scanning devices folder for changes.
20/013/2016 23:13:50 - INFO - Changes have been found. Doing a hard reset (removing user modifications).
20/013/2016 23:13:51 - INFO - Pulling changes from github.
20/013/2016 23:13:52 - INFO - Quietly closing devices repository.
20/013/2016 23:13:52 - INFO - Devices sync finished.
20/013/2016 23:13:52 - INFO - Loading devices database
20/013/2016 23:13:52 - INFO - Loaded 94 devices
20/013/2016 23:13:52 - INFO - Starting phone detection
20/013/2016 23:13:56 - INFO - Device connected in fastboot mode
20/014/2016 23:14:08 - INFO - Now plug your device in Fastboot Mode
20/014/2016 23:14:09 - INFO - Fetching fastboot version info from connected device
20/014/2016 23:14:09 - INFO - FASTBOOT version info: [ version: 0.5 ]
20/014/2016 23:14:14 - INFO - Device Status: FASTBOOT mode
20/014/2016 23:14:22 - INFO - Now plug your device in Fastboot Mode
20/014/2016 23:14:23 - INFO - Fetching connected device info
20/014/2016 23:14:23 - INFO - Connected device info: [ PSDN:BX903H4MCT&ZLP ]
20/014/2016 23:14:42 - INFO - Please connect your device into flashmode.
20/014/2016 23:14:46 - INFO - Device disconnected
20/014/2016 23:14:54 - INFO - Device connected in flash mode
20/014/2016 23:14:54 - INFO - Opening device for R/W
20/014/2016 23:14:54 - INFO - Reading device information
20/014/2016 23:14:54 - INFO - Phone ready for flashmode operations.
20/014/2016 23:14:54 - INFO - Opening TA partition 2
20/014/2016 23:14:54 - INFO - Current device : LT25i - BX903H4MCT - 1268-5967_R2J - 1264-2336_9.2.A.2.5 - GLOBAL-LTE_9.2.A.2.5
20/014/2016 23:14:54 - INFO - Closing TA partition
20/014/2016 23:14:54 - INFO - No loader in the bundle. Searching for one
20/014/2016 23:14:55 - INFO - Processing loader.sin
20/014/2016 23:14:55 - INFO - Checking header
20/014/2016 23:14:55 - INFO - Flashing data
20/014/2016 23:14:59 - INFO - Loader : S1_Root_7054 - Version : R5A058 / Boot version : R11AB029 / Bootloader status : UNROOTABLE
20/014/2016 23:14:59 - INFO - Max packet size set to 64K
20/014/2016 23:14:59 - INFO - Opening TA partition 2
20/015/2016 23:15:00 - INFO - Start Reading unit 00 00 08 B2
20/015/2016 23:15:00 - INFO - Reading TA finished.
20/015/2016 23:15:00 - INFO - Closing TA partition
20/015/2016 23:15:00 - INFO - Ending flash session
20/015/2016 23:15:00 - INFO - Your phone bootloader cannot be officially unlocked
20/015/2016 23:15:00 - INFO - You can now unplug and restart your phone
20/015/2016 23:15:00 - INFO - Device connected in flash mode
20/015/2016 23:15:01 - INFO - Device disconnected
20/015/2016 23:15:03 - INFO - Device connected in flash mode
20/016/2016 23:16:48 - INFO - Selected Bundle for Sony Xperia V(LT25i). FW release : 9.2.A.2.5. Customization : CE4
20/016/2016 23:16:48 - INFO - Preparing files for flashing
20/016/2016 23:16:57 - INFO - Please connect your device into flashmode.
20/016/2016 23:16:58 - INFO - Opening device for R/W
20/016/2016 23:16:58 - INFO - Reading device information
20/016/2016 23:16:58 - INFO - Phone ready for flashmode operations.
20/016/2016 23:16:58 - INFO - Opening TA partition 2
20/016/2016 23:16:58 - INFO - Current device : LT25i - BX903H4MCT - 1268-5967_R2J - 1264-2336_9.2.A.2.5 - GLOBAL-LTE_9.2.A.2.5
20/016/2016 23:16:58 - INFO - Closing TA partition
20/016/2016 23:16:58 - INFO - Start Flashing
20/016/2016 23:16:58 - INFO - Processing loader.sin
20/016/2016 23:16:58 - INFO - Checking header
20/016/2016 23:16:58 - INFO - Flashing data
20/016/2016 23:16:58 - INFO - Device connected in flash mode
20/017/2016 23:17:03 - INFO - Loader : S1_Root_7054 - Version : R5A058 / Boot version : R11AB029 / Bootloader status : UNROOTABLE
20/017/2016 23:17:03 - INFO - Max packet size set to 64K
20/017/2016 23:17:03 - INFO - USB buffer size set to 512K
20/017/2016 23:17:03 - INFO - No flash script found. Using 0.9.18 flash engine
20/017/2016 23:17:03 - INFO - Disabling final data verification check
20/017/2016 23:17:03 - INFO - Disabling final verification
20/017/2016 23:17:03 - INFO - Opening TA partition 2
20/017/2016 23:17:03 - INFO - Writing TA unit 00002774. Value : 01
20/017/2016 23:17:03 - INFO - Closing TA partition
20/017/2016 23:17:03 - INFO - Opening TA partition 2
20/017/2016 23:17:03 - INFO - Closing TA partition
20/017/2016 23:17:03 - INFO - Opening TA partition 2
20/017/2016 23:17:03 - INFO - Closing TA partition
20/017/2016 23:17:03 - INFO - Opening TA partition 2
20/017/2016 23:17:03 - INFO - Processing system.sin
20/017/2016 23:17:03 - INFO - Checking header
20/017/2016 23:17:04 - ERROR - Processing of system.sin finished with errors.
20/017/2016 23:17:04 - INFO - Ending flash session
20/017/2016 23:17:04 - ERROR -
20/017/2016 23:17:04 - ERROR - Error flashing. Aborted
20/017/2016 23:17:04 - INFO - Flashing finished.
20/017/2016 23:17:04 - INFO - Please unplug and start your phone
20/017/2016 23:17:04 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings
20/017/2016 23:17:04 - INFO - Device connected in flash mode
20/017/2016 23:17:06 - INFO - Device disconnected
20/017/2016 23:17:08 - INFO - Device connected in flash mode

Anyone any idea?