Other than that its Lenovo own design/restrictions… their in the business to sell and make money!
Good luck
EDIT: Sorry, cant help you with that.
Depending how your thinking about the method for flashing a mod file on a LENOVO system with bootguard… and dont ask me how to bypass security checks and best method or safest one without bricking the system board…, working on a current dump from the bios_region could be a better option, using Intel FPT tool from MEI package according your chipset ME FW version.
Intel (Converged Security) Management Engine: Drivers, Firmware and Tools (2-15) - Special Topics / Intel Management Engine - Win-Raid Forum (level1techs.com)
The AMI BIOS Guard Extractor is correct for that operation you’ve done.
Thats it, you should wait for others users contribution on your request.
EDIT: Dump tools on the linked thread, the rest i cant assist you as already told before.