Secure flash won't let me

[ganonleboucher]

System

• Laptop: Eluktronics MECH 15 G3 with Intel i7 10875H
• BIOS Version: 1.16
• GPU: Nvidia RTX 2070 SUPER (Max-P)
• [v] CSM is turned off. Make sure to confirm this in the BIOS and not with GPU-Z or similar since it can be inaccurate
• [can't confirm in BIOS] 4G decoding is enabled. Make sure to confirm this in the BIOS and not with GPU-Z or similar since it can be inaccurate
• [v] UEFIPatch is applied (see Using UEFIPatch for more information). On some motherboards DSDT Patching is also needed
• [v] I have read Common issues (and fixes)

Description
Here is my journey :

• Contact your support for the BIOS
• Format my USB drive to a FAT32 file system
• Copy of the file given by your support
• Boot on the USB drive to end up on the shell
• Enter the following DOS command :
  fs4:
  ls
  F.nsh
• Enter in AMI Firmware Update Utility v5.12
• I notice my current BIOS version is 1.12 and it's gonna update to 1.16
• Press enter to launch the update
• Few reboot later the BIOS is successfully updated and i boot on my windows
• Joy, now i'm sure the .rom file work perfectly
• Downloading latest release of NvStrapsReBar : https://github.com/terminatorul/NvStrapsReBar/releases/tag/v0.4
• Install of UEFITool
• Adding FFS module as explain in tutorial : https://github.com/xCuri0/ReBarUEFI/wiki/Adding-FFS-module
• Using UEFIPatch as explain in tutorial : https://github.com/xCuri0/ReBarUEFI/wiki/Using-UEFIPatch
• Output shell say "No patches can be applied" and i don't have Intel 7/8/9 Series Chispet so i continue to next step
• Checking for pad file issue : no problem found
• Skipping DSDT Patching because I do not have a motherboard which requires it : https://github.com/xCuri0/ReBarUEFI/wiki/DSDT-Patching
• Now i have a patched .rom file, I copy it to the USB Drive use in the previous BIOS update and rename it GMxMQPxxN116.ROM for override the one provided by Eluktronics Support
• Boot on the USB drive to end up on the shell
• Enter the following DOS command :
  fs4:
  ls
  F.nsh
• Enter in AMI Firmware Update Utility v5.12
• Current BIOS version is 1.16 and the update is 1.16
• Press enter to launch the update
• After " Loading capsule to secure memory buffer ... Done" i get "18- Error: Secure Flash Rom Verify fail.

Here is what inside the content of F.nsh :

 @cls
 @echo WARNING: This utility will reprogram the whole SPI Flash chip which
 @echo WARNING: includes system BIOS, TXE or ME firmware!!!
 @echo WARNING: DO NOT continue unless you are 100% sure you want to do this.
 @echo WARNING: To stop, turn off your computer and remove the update media,
 @echo WARNING: or do not run THIS SCRIPT.
 @pause
 @cls
@AfuEfix64.efi GMxMQPxxN116.ROM /p /b /n /r /x /l /e /capsule /reboot

I add the /capsule myself after finding option here to try to bypass secure boot but the result is the same.

The support of Eluktronic told me that this product is end of life for BIOS/EC updates and are not interrested to help me with.

I would appreciate any help