Download mode bug

Hello,

My LG G3 (D855 16go) is hard bricked.

I have the qualcomm 9008 Usb connection and I have flashed correctly, following the topic (http://ift.tt/1Xi6FQR)

When I flash sbl1 at the end, I try to get in download mode .
I see the screen download mode during 2 sec, and then black screen and I get back the qualcomm 9008 USB connection.
I have tried many times to flash (V10 tot or V20), but I don't know what to do.

Could someone give me a solution, please?

PS: I have tried LGUP ,but I have model unkown and i cannot select
PS2:With flashtool, I put the port 41 and when I want to flash i got the Download FAIL!!, Model Information Check Fail (with PID:NULL,IMEI:NULL,Model(nothing),DLL : D855
PS3:with Flashtool 2014,I get stuck at 4%(Upgrading S/W)

I have spent some many hours reading topics in xda or googling but I am stuck. So please help if you have an idea

Thanks,

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