The following article provides information about resolving an error that is seen when running the TPM firmware update using the Command Line Interface.
Running the TPM module firmware update 7.2.0.2 from PowerShell or Command Prompt, will fail when using the /s switch. The log displays an error Exit Code = 8 (Downgrade Ban Error) when the update is run using the /s and /l switches.
*************************************************
***Dell Firmware Update started on 5/7/2019 at 13:33:10***
Command: C:\_SMSTaskSequence\Packages\CM10011F\DELLTPM_NPCT750_20_7.2.0.2_64.exe /s /p= /l=C:\Temp\tpm2.log
WSMT Supported: Using WMI commands.
Registry creation is Success at \SOFTWARE\DELL\FirmwareUpdate
RemainingFlashes = 127
--------------------------------
--------------------------------
Error: New TPM payload is older or same as the current TPM payload. Downgrade is not allowed.
Exit Code = 8 (Downgrade Ban Error)
***Dell Firmware Update finished at 5/7/2019 at 13:33:10***
There was an issue with the installer when using the /s switch. Dell's engineering has released a new version of the firmware.
Ensure you are using the latest version of the firmware
Or
Install the update manually
Go to the Dell Support Site
Enter the service tag or express service code to get drivers specific to how the system shipped
Alternatively you can choose your system type from the product list to get a general list of drivers for that system
Click the Drivers and Downloads drawer in the menu
Ensure you have the correct operating system set
Select Security from the category dropdown
Locate the Dell TPM 2.0 Firmware Update Utility Ver. 7.2.0.2 V1, A01 or newer
Click the download link and follow the online instructions