Remove UEFI Password from Surface Book 1

Hi all,

I bought a Surface Book first generation on Ebay. Unfortunately the device has a UEFI / BIOS Password and the seller doesn’t remember this.
also the device is Bitlocker locked and won’t boot into windows (Password as well unknown).

Luckily the USB Boot is not disabled and I was able to boot a normal windows installation USB drive. So I can reinstall windows and this should work.
i also worked myself through this thread (Remove UEFI Password from Surface Pro 6 by flashing UEFI without opening the device? (Sorry not allowed to past the direct link #newuser)) and wanted to prepare all the needed information. Unfortunately I was not able too create the boot USB Stick. I followed the instructions on CHIPSEC Documentation (Sorry not allowed to past the direct link #newuser) but the stick won’t boot. I also tried to use the working Windows install stick and added all files and replaced the “Bootx64.efi” with the file from the Documentation. unfortunately also then the stick won’t boot.
Can you help me please and give me a short guidance.

Thanks in advanced
Marcel