Unbrick Lenovo Tab 4 8 plus (TB-8704F/X)

Hey There,

i have a TB-8704F and accidentially bricked it.

What i can't do:

- boot andoid
- boot recovery
- boot fastboot

What i can do:

- Connect to PC via USB and a new COM-Port pops up "Qualcomm HS-USB Diagnostics 900E"

However in order to "deep" flash it i would need to enable QDL / EDL mode. But i don't know how. I have already tried combinations of volume +/- buttons and powering the device on / plug in USB. Reinstalled the USB drivers, but i never get the "Qualcomm HS-USB QDLoader 9008" device to show up.

I have now opend the back cover as i read online, that there might be a test pin to get EDL working. (see attached photo)

I found a youtube video online where someone seems to enable edl mode. Not realy sure what happens there, as i don't speak hindi.

Has anyone got experience with this how to get the device to switch to EDL mode instead of diagnostics?

I am happy for every response/hint/whatsoever.

It should be possible imo - someone did it with another lenovo tablet. After all the tablet is from the same generation but has a 10" screen instead of 8".