"The capsule file failed in the security compliance check" error while updating BIOS on Intel S2600cp Server Board

While attempting to update the BIOS on an Intel S2600cp server system board I receive an error that says "The capsule file failed in the security compliance check. Please refer to BIOS release notes for details." The BIOS update doesn't complete successfully.

This is happening on two server boards that I just bought both used that that are both currently running BIOS version 1.04.2096.

I am attempting to update to Intel® Server Board S2600CP Firmware Update Package for EFI Version: 02.06.0006 which I have downloaded directly from the Intel website https://downloadcenter.intel.com/download/26957/Intel-Server-Board-S2600CP-Firmware-Update-Package-for-EFI?product=61088.

What do I need to do to fix this issue?

I have followed the instructions on the website for creating the bootable flash drive for installing this BIOS update by formatting the drive with the FAT file system and then copying the extracted files directly to the thumb drive.

The flash drive boots fine, provides me with the usual option and I choose option 1 to update the firmware and then option 2 to update the BIOS. Or I get the same error if I choose option 2 to update the BIOS.

I even used the same thumb drive that had this BIOS update on it that I had previously used to update the BIOS on another S2600cp server board (that was running a newer version of the BIOS) and this other server board updated successfully and without any issues at all. Now I am unable to update the BIOS on these two other S2600cp server boards that are running the older BIOS version.

I have recreated this bootable flash drive, have created the bootable flash drive on a different flash drive, have reset the BIOS to the default settings, and have examined the BIOS settings but so far haven't found any solutions that have fixed this issue.

What else can I do to fix this issue so that I can successfully update to this latest version of the BIOS? Do I first need to update to a newer (but not the most recent version of the BIOS) and then I will be able to update to the latest BIOS version?