I have not been able to figure out how to enable Secure Boot on a Dell Networking VEP 4600 16 Core.

I have used the Dell UFW 3.8 (Unified Firmware Updater) using update ALL to update the BIOS, BMC and CPLD to the latest versions. The boot process shows all the latest being active. 

From the Dell support page for the devices service tag I followed the information in:

VEP4600 BIOS User Guide., 11 May 2023 Section

Dell Technologies VEP4600 BIOS User guide  > BIOS > Secure Boot

On the Security tab of the BIOS under section Secure Boot option, I am not able to change Secure Boot from Disabled to Enabled that option is grayed out.

Note: I have CSM on the Advanced section of the BIOS to disable without