M5X does not start after firmware update

Hello

I have performed a firmware update (M5X(T1006X)-Android8.0-ALLDOCUBE-20190601.rar) using latest flash tool (SP_Flash_Tool_v5.1944_Win.zip), using tutorial listed here which points here.

The tutorial looks pretty straight forward, maybe except Step 8 which contains an instruction to Untick the Preloader option (which I did, of course).

The process seems to pass correctly, yellow progress bars, then the big green circle saying Success.

But the tablet does not start anymore.

I can repeat the step (I did like 10 times or  so), still the same result.

Looking around the internet I can see comments on the instructions used that one step is missing: change Download option to Firmware update option (eg. here).

What is a proper procedure to upgrade firmware on Alldocube M5X?

How can I bring my tablet back to life?

thanks for help.

Stan

please show me serial number of  your tablet!

and a pic which show the error!