17 R5, BIOS recovery from 1.11.0 to 1.8.1

Hello, I am trying to recover bios (downgrade from 1.11.0 to 1.8.1)

I followed these links which show similar steps :

1) https://www.dell.com/community/Alienware-Desktops/Aurora-R6-BIOS-stuck-on-recover-BIS-after-a-failed-update/td-p/6234909

2) http://forum.notebookreview.com/threads/force-downgrade-alienware-area-51m-bios-or-any-alienware-to-locked-lower-versions.829542/

But on the step where I CTRL+ESC (HOLD)+ POWER ON, I get the code "3 red, 4 blue" which is : 

"Recovery image found but invalid"
and show me to this screen :

My laptop is working fine. I just want to rollback my BIOS back to 1.8.1.

Thanks.