Reverting back from Lineage to stock ROM not working: error in Flashtool

[PepperAlf]

Hello,

I want to go back to stock ROM on my SGP771 but Flashtool always gives me an error when trying to flash.
I tried different ftf files:

SGP771_28.0.A.8.251_R6A_Customized DE_1295-6955
SGP771_Customized DE_1295-6955_32.2.A.5.11_R4C
SGP771_Customized DE_1295-6955_32.4.A.0.160_R1E

Here's what I get right after flashing starts:

FlashTool 0.9.23.2

08/041/2017 14:41:22 - INFO - Start Flashing
08/041/2017 14:41:22 - INFO - Processing loader.sin
08/041/2017 14:41:22 - INFO - Checking header
08/041/2017 14:41:22 - INFO - Flashing data
08/041/2017 14:41:23 - INFO - Loader : S1_Root_f936 - Version : MSM8994_50 / Boot version : S1_Boot_MSM8994_LA1.2.3_45 / Bootloader status : ROOTED
08/041/2017 14:41:23 - INFO - Max packet size set to 4M
08/041/2017 14:41:23 - INFO - USB buffer size set to 512K
08/041/2017 14:41:23 - INFO - Parsing boot delivery
08/041/2017 14:41:23 - INFO - Ending flash session
08/041/2017 14:41:23 - ERROR - null
08/041/2017 14:41:23 - ERROR - Error flashing. Aborted
08/041/2017 14:41:23 - INFO - Device connected in flash mode

Can anyone help me out? I'm a little bit of a beginner. But I did manage to backup my TA partition. So if someone could give me a guide how to revert the tablet back to its original state this would be much appreciated.

 

[tapppple]

Uninstall your current flashtool, install old version 0.9.18.6 and flash any firmware. (I chose MM 5.11)
If it still not works then exclude, i remember, boot bundle.sin.

 

[PepperAlf]

Uninstall your current flashtool, install old version 0.9.18.6 and flash any firmware. (I chose MM 5.11)
If it still not works then exclude, i remember, boot bundle.sin.

Excluding boot bundle.sin worked. Thanks a lot!!