You can try a dump made with the Intel TXE4 tools
[Intel (Converged Security) Trusted Execution Engine: Drivers, Firmware and Tools - Special Topics / Intel Management Engine - Win-Raid Forum (level1techs.com)](https://winraid.level1techs.com/t/intel-converged-security-trusted-execution-engine-drivers-firmware-and-tools
EDIT: Thats not a full backup, just bios region, you should do an -d only (-d full_spi.bin), we never know if anything goes wrong and need a full image for programmer, thats the risks of bios mod.
With the flash cmd -f , using same biosreg.bin backup, you can try and see if will let write on the spi or if the regions are locked. The tools MEinfo/FPT -verbose/-debug also give some info about, besides the fpt -f, be very careful with the tools and what you flash. Good luck