If you have a dump of the SPI flash of a Lenovo Thinkpad (newer than T4x I guess) you may try this tool and get some info about the different regions of the flash (descriptor table, BIOS, Intel ME, ...

If your BIOS version is equal or lower, skip to the Examining protections section. If not, go through the downgrade process, described next. Go to the Lenovo web site and download BIOS Update Bootable ...

Lenovo Vantage is a useful driver manager and installer native to Lenovo PCs and laptops that can also perform BIOS updates when necessary. It can also be downloaded to non-Lenovo devices, and it’s ...