[Xperia Z3 Compact General] gruinelli:
For me it seems not to work as expected :(

Any hint would be appreciated.

I had a stack Sony Z3C and unlocked the Bootloader.

It is on the latest release, meaning Android 6.0.1 and build 23.5.A.1.291.

So based on this thread, I tried to downgrade to .575 but it seems to have no impact.

The flashtool log seems to be ok, but when i boot next i still am on 291.

Log:

11/051/2016 18:51:25 - INFO - Flashtool Version 0.9.22.3 built on 08-06-2016 22:30:00
11/051/2016 18:51:25 - INFO - Executing search strategies to find proxy selector
11/051/2016 18:51:25 - INFO - No proxy found for IE. Trying next one
11/051/2016 18:51:26 - INFO - No proxy found for firefox. Trying next one
11/051/2016 18:51:26 - INFO - No proxy found for java. Trying next one
11/051/2016 18:51:26 - INFO - Syncing devices from github
11/051/2016 18:51:26 - INFO - Opening devices repository.
11/051/2016 18:51:26 - INFO - Scanning devices folder for changes.
11/051/2016 18:51:32 - INFO - Pulling changes from github.
11/051/2016 18:51:33 - INFO - Quietly closing devices repository.
11/051/2016 18:51:33 - INFO - Devices sync finished.
11/051/2016 18:51:33 - INFO - Loading devices database
11/051/2016 18:51:33 - INFO - Loaded 94 devices
11/051/2016 18:51:33 - INFO - Starting phone detection
11/051/2016 18:51:37 - INFO - Device disconnected
11/052/2016 18:52:23 - INFO - Selected Bundle for Sony Xperia Z3 Compact(D5803). FW release : 23.5.A.0.575_R3D. Customization : stock kernel
11/052/2016 18:52:23 - INFO - Preparing files for flashing
11/052/2016 18:52:23 - INFO - Please connect your device into flashmode.
11/052/2016 18:52:30 - INFO - Device connected in flash mode
11/052/2016 18:52:31 - INFO - Opening device for R/W
11/052/2016 18:52:31 - INFO - Reading device information
11/052/2016 18:52:31 - INFO - Phone ready for flashmode operations.
11/052/2016 18:52:31 - INFO - Opening TA partition 2
11/052/2016 18:52:31 - INFO - Current device : D5803 - YT910ZSLFT - 1289-4008_R6D - 1285-6521_23.5.A.0.575 - GLOBAL-LTE_23.5.A.1.291
11/052/2016 18:52:31 - INFO - Closing TA partition
11/052/2016 18:52:31 - INFO - Start Flashing
11/052/2016 18:52:31 - INFO - Processing loader.sin
11/052/2016 18:52:31 - INFO - Checking header
11/052/2016 18:52:31 - INFO - Flashing data
11/052/2016 18:52:32 - INFO - Loader : S1_Root_9c84 - Version : MSM8974AB_27 / Boot version : S1_Boot_MSM8974AC_LA3.0_M_2 / Bootloader status : ROOTED
11/052/2016 18:52:32 - INFO - Max packet size set to 512K
11/052/2016 18:52:32 - INFO - USB buffer size set to 512K
11/052/2016 18:52:32 - INFO - Parsing boot delivery
11/052/2016 18:52:56 - INFO - Found a template session. Using it : C:\Users\gruinelli\.flashTool\devices\D58XX\default.fsc
11/052/2016 18:52:56 - INFO - Opening TA partition 2
11/052/2016 18:52:56 - INFO - Writing TA unit 00002774. Value : 01
11/052/2016 18:52:56 - INFO - Closing TA partition
11/052/2016 18:52:57 - WARN - partition is excluded from bundle
11/052/2016 18:52:57 - INFO - Opening TA partition 2
11/052/2016 18:52:57 - INFO - Closing TA partition
11/052/2016 18:52:57 - INFO - Opening TA partition 2
11/052/2016 18:52:57 - INFO - Writing TA unit 0000084F. Value : 1A CE 28 00 01 00 06 05 00 02 02 08 00 10 03 00 02 04 02 05 00 01 03 02 00 10 05 00 03 03 05 00 10 05 00 05 83 02 00 10 02 00 05 85 12 00 02 00 A9 09 BE BA A9 09 00 00 B3 08 BE BA B3 08 00 00 04 00 03 00 02 00 04 00 04 00 B0 04 0E 00 06 00 B8 0B 01 4B 00 00 00 03 96 00 2C 01 03 00 09 00 01
11/052/2016 18:52:57 - INFO - Writing TA unit 000008FD. Value : 00
11/052/2016 18:52:57 - INFO - Closing TA partition
11/052/2016 18:52:57 - INFO - Opening TA partition 2
11/052/2016 18:52:57 - INFO - Processing dbi_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID12-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:57 - INFO - Processing emmc_appsboot_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID09-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:57 - INFO - Processing rpm_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID0A-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:57 - INFO - Processing s1sbl_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID65-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:57 - INFO - Processing sbl1_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID00-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:57 - INFO - Processing tz_S1_Boot_MSM8974AC_LA3_0_M_2_AID_4_PLATFORM-MSM8974AC-LIVE-HWID007B40E1-SWID07-OEM1-AID4-DEBUG00_S1-BOOT-LIVE-9C84-0004-MMC.sin
11/052/2016 18:52:57 - INFO - Checking header
11/052/2016 18:52:57 - INFO - Flashing data
11/052/2016 18:52:58 - INFO - Closing TA partition
11/052/2016 18:52:58 - INFO - Opening TA partition 2
11/052/2016 18:52:58 - WARN - cache is excluded from bundle
11/052/2016 18:52:58 - WARN - apps_log is excluded from bundle
11/052/2016 18:52:58 - INFO - Processing kernel.sin
11/052/2016 18:52:58 - INFO - Checking header
11/052/2016 18:52:58 - INFO - Flashing data
11/053/2016 18:53:00 - WARN - fotakernel is excluded from bundle
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - WARN - userdata is excluded from bundle
11/053/2016 18:53:00 - WARN - system is excluded from bundle
11/053/2016 18:53:00 - WARN - amss_fs_1 is excluded from bundle
11/053/2016 18:53:00 - WARN - amss_fs_2 is excluded from bundle
11/053/2016 18:53:00 - WARN - amss_fsg is excluded from bundle
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - WARN - Unit 2212 not found in bundle
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - WARN - Unit 2404 not found in bundle
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - WARN - elabel is excluded from bundle
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Opening TA partition 2
11/053/2016 18:53:00 - INFO - Writing TA unit 00002725. Value : 32 30 31 36 2D 31 32 2D 31 31 20 31 38 3A 35 33 3A 30 30 00
11/053/2016 18:53:00 - INFO - Writing TA unit 00002774. Value : 00
11/053/2016 18:53:00 - INFO - Closing TA partition
11/053/2016 18:53:00 - INFO - Ending flash session
11/053/2016 18:53:00 - INFO - Flashing finished.
11/053/2016 18:53:00 - INFO - Please unplug and start your phone
11/053/2016 18:53:00 - INFO - For flashtool, Unknown Sources and Debugging must be checked in phone settings

I now also flashed a complete new image (pre-rooted) from http://xdaforums.com/z3-compact/development/list-pre-rooted-firmwares-6-oct-2015-t3218820, I however still seem not to have a rooted device (as supersu sais). Also the downgrade also doesn't work with that image.

What am I missing?

Do I first have to install another bootloader? (The guide seems to say no).

Is the CDA relevant? I seemed to have ne from the UK but got the phone in Switzerland.

Should the FSC Script be used or not?