i have this problem,
My Xperia C2304 not flashing.
this is a log info:
12/018/2018 11:18:41 - INFO - Selected Bundle for Sony Xperia C(C2304). FW release : 16.0.B.2.16. Customization : Customized BR
12/018/2018 11:18:41 - INFO - Preparing files for flashing
12/018/2018 11:18:52 - INFO - Please connect your device into flashmode.
12/018/2018 11:18:53 - INFO - Opening device for R/W
12/018/2018 11:18:53 - INFO - Reading device information
12/018/2018 11:18:53 - INFO - Phone ready for flashmode operations.
12/018/2018 11:18:53 - INFO - Opening TA partition 2
12/018/2018 11:18:53 - INFO - Current device : C2304 - LQ4A16B12549 - 1278-6902_R4A - 1275-5177_16.0.B.2.16 - WORLD-a_16.0.B.2.16
12/018/2018 11:18:53 - INFO - Closing TA partition
12/018/2018 11:18:53 - INFO - Start Flashing
12/018/2018 11:18:53 - INFO - No loader in the bundle. Searching for one
12/018/2018 11:18:53 - INFO - No matching loader found
12/018/2018 11:18:53 - WARN - No loader found or set manually. Skipping loader
12/018/2018 11:18:53 - INFO - Loader : S1_Root_bb35 - Version : 2.14.J.2.16 / Boot version : 2.14.J.2.16 / Bootloader status : NOT_ROOTABLE
12/018/2018 11:18:53 - INFO - Max packet size set to 64K
12/018/2018 11:18:53 - INFO - USB buffer size set to 512K
12/018/2018 11:18:53 - INFO - No flash script found. Using 0.9.18 flash engine
12/018/2018 11:18:53 - INFO - Disabling final data verification check
12/018/2018 11:18:53 - INFO - Disabling final verification
12/018/2018 11:18:54 - INFO - Ending flash session
12/018/2018 11:18:54 - ERROR -
12/018/2018 11:18:54 - ERROR - Error flashing. Aborted
12/018/2018 11:18:54 - INFO - Flashing finished.
12/018/2018 11:18:54 - INFO - Please unplug and start your phone
12/018/2018 11:18:54 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings
12/018/2018 11:18:54 - INFO - Device connected in flash mode
12/018/2018 11:18:54 - INFO - Device disconnected
I'm having the exact same problem, I tried on old and new versions of FlashTool, different ROMs, etc.
14/045/2020 15:45:03 - INFO - Flashtool Version 0.9.23.1 built on 11-01-2017 15:12:00
14/045/2020 15:45:03 - INFO - Executing search strategies to find proxy selector
14/045/2020 15:45:04 - INFO - No proxy found for IE. Trying next one
14/045/2020 15:45:04 - INFO - Strategy firefox failed trying next one : No Firefox installation found
14/045/2020 15:45:04 - INFO - No proxy found for java. Trying next one
14/045/2020 15:45:05 - INFO - Syncing devices from github
14/045/2020 15:45:07 - INFO - Opening devices repository.
14/045/2020 15:45:08 - INFO - Scanning devices folder for changes.
14/045/2020 15:45:09 - INFO - Pulling changes from github.
14/045/2020 15:45:11 - INFO - Quietly closing devices repository.
14/045/2020 15:45:11 - INFO - Devices sync finished.
14/045/2020 15:45:11 - INFO - Loading devices database
14/045/2020 15:45:11 - INFO - Loaded 1 devices
14/045/2020 15:45:11 - INFO - Starting phone detection
14/045/2020 15:45:16 - INFO - Device disconnected
14/045/2020 15:45:23 - INFO - Device connected in flash mode
14/045/2020 15:45:38 - INFO - Selected Bundle for Sony Xperia C(C2304). FW release : 16.0.B.2.16. Customization : Customized BR
14/045/2020 15:45:38 - INFO - Preparing files for flashing
14/045/2020 15:45:42 - INFO - Device disconnected
14/048/2020 15:48:42 - INFO - Please connect your device into flashmode.
14/048/2020 15:48:53 - INFO - Device connected in flash mode
14/049/2020 15:49:02 - INFO - Opening device for R/W
14/049/2020 15:49:03 - INFO - Reading device information
14/049/2020 15:49:04 - INFO - Phone ready for flashmode operations.
14/049/2020 15:49:04 - INFO - Opening TA partition 2
14/049/2020 15:49:04 - INFO - Current device : C2304 - LQ4401B09584 - 1278-6902_R4A - 1275-5177_16.0.B.2.16 - WORLD-a_16.0.B.2.16
14/049/2020 15:49:06 - INFO - Closing TA partition
14/049/2020 15:49:06 - INFO - Start Flashing
14/049/2020 15:49:06 - INFO - Processing loader.sin
14/049/2020 15:49:06 - INFO - Checking header
14/049/2020 15:49:06 - INFO - Flashing data
14/049/2020 15:49:07 - INFO - Loader : S1_Root_bb35 - Version : MT6589_12 / Boot version : 2.14.J.2.16 / Bootloader status : NOT_ROOTABLE
14/049/2020 15:49:07 - INFO - Max packet size set to 512K
14/049/2020 15:49:07 - INFO - USB buffer size set to 512K
14/049/2020 15:49:25 - INFO - No flash script found. Using 0.9.18 flash engine
14/049/2020 15:49:25 - INFO - Opening TA partition 2
14/049/2020 15:49:25 - INFO - Writing TA unit 00002774. Value : 01
14/049/2020 15:49:25 - INFO - Closing TA partition
14/050/2020 15:50:09 - INFO - Ending flash session
14/050/2020 15:50:09 - ERROR -
14/050/2020 15:50:09 - ERROR - Error flashing. Aborted
14/050/2020 15:50:09 - INFO - Flashing finished.
14/050/2020 15:50:09 - INFO - Please unplug and start your phone
14/050/2020 15:50:09 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings
14/050/2020 15:50:10 - INFO - Device disconnected