Fail to backup TA - fail to install recovery

Hi,

I need help for backup TA and install TWRP recovery.

I have a Xperia SP Jelly 4.3 firmware 205 rooted, locked bootloader (unlock allowed), and want to use flashtool to save TA partiton and install TWRP (no recovery installed yet).
I have installed all drivers, Pc companion off, antivirus off, Sony USB cable, windows 10 x64.

• Impossible to save TA with Backup-TA (I read the entire thread in developpement section and download/tried all the solutions there. As I am not allowed to post there, I post here). Here is the error :
  
  Code:

  ---

      =======================================
    FIND TA PARTITION
    =======================================
  Partition found!
    =======================================
    BACKUP TA PARTITION
    =======================================
    dd: can't open '/sdcard/backupTA.img': No such file or directory
    =======================================
    INTEGRITY CHECK
    =======================================
    FAILED - Backup does not match TA Partition. Please try again.

    *** Backup unsuccessful. ***

  ---

• Even in flashtool, can't save TA nor install TWRP
  
  Code:

  ---

  27/059/2016 21:59:30 - INFO  - <- This level is successfully initialized
27/059/2016 21:59:31 - INFO  - Flashtool Version 0.9.22.3 built on 08-06-2016 22:30:00
27/059/2016 21:59:31 - INFO  - Executing search strategies to find proxy selector
27/059/2016 21:59:31 - INFO  - No proxy found for IE. Trying next one
27/059/2016 21:59:31 - INFO  - No proxy found for firefox. Trying next one
27/059/2016 21:59:31 - INFO  - No proxy found for java. Trying next one
27/059/2016 21:59:31 - INFO  - Syncing devices from github
27/059/2016 21:59:32 - INFO  - Opening devices repository.
27/059/2016 21:59:32 - INFO  - Scanning devices folder for changes.
27/059/2016 21:59:39 - INFO  - Pulling changes from github.
27/059/2016 21:59:40 - INFO  - Quietly closing devices repository.
27/059/2016 21:59:40 - INFO  - Devices sync finished.
27/059/2016 21:59:40 - INFO  - Loading devices database
27/059/2016 21:59:40 - INFO  - Loaded 91 devices
27/059/2016 21:59:40 - INFO  - Starting phone detection
27/059/2016 21:59:46 - INFO  - Device connected with USB debugging on
27/059/2016 21:59:46 - INFO  - Connected device : Sony Xperia SP
27/059/2016 21:59:46 - INFO  - Installed version of busybox : BusyBox v1.22.1-Stericson (2014-01-25 17:27:18 CET) multi-call binary.
27/059/2016 21:59:46 - INFO  - Android version : 4.3 / kernel version : 3.4.0-perf-g4c8352f-00775-g89dacae / Build number : 12.1.A.1.205
27/059/2016 21:59:46 - INFO  - Checking root access
27/059/2016 21:59:46 - INFO  - Root Access Allowed
27/059/2016 21:59:52 - INFO  - Begin backup of /dev/block/platform/msm_sdcc.1/by-name/TA
27/059/2016 21:59:52 - ERROR - Erreur when doing raw backup
27/000/2016 22:00:36 - INFO  - Now plug your device in Fastboot Mode
27/000/2016 22:00:40 - INFO  - Device disconnected
27/001/2016 22:01:21 - INFO  - Device connected in fastboot mode
27/001/2016 22:01:33 - INFO  - Selected kernel (boot.img or kernel.sin): C:\Users\Someone\Downloads\twrp-3.0.2-r12-boot-huashan.img
27/001/2016 22:01:33 - INFO  - Flashing selected kernel
27/001/2016 22:01:33 - INFO  - sending 'boot' (12253 KB)...
27/001/2016 22:01:33 - INFO  - FAILED (remote: The Device must be rooted first)
27/001/2016 22:01:33 - INFO  - finished. total time: 0.007s
27/001/2016 22:01:33 - INFO  - FASTBOOT Output:
 sending 'boot' (12253 KB)...
FAILED (remote: The Device must be rooted first)
finished. total time: 0.007s
27/001/2016 22:01:33 - INFO  - Please check the log before rebooting into system

  ---

I don't understand what is missing, can't find any solution that worked...
Thanks for any clue.

from xda-developers http://ift.tt/290foac
via IFTTT