Supermicro SuperServer SYS-E403-9D-16C-IPD2 User Manual page 111

 Key Exchange Keys (KEK)
Update
Select Yes to load a factory default KEK or No to load from a file on an external media.
Append
Select Yes to add the KEK from the manufacturer's defaults list to the existing KEK. Select
No to load the KEK from a file. The options are Yes and No.

Authorized Signatures
Update
Select Yes to load a factory default db or No to load from a file on an external media.
Append
Select Yes to add the db from the manufacturer's defaults list to the existing db. Select No
to load the db from a file. The options are Yes and No.

Forbidden Signatures
Update
Select Yes to load a factory default dbx or No to load from a file on an external media.
Append
Select Yes to add the dbx from the manufacturer's defaults list to the existing dbx. Select
No to load the dbx from a file. The options are Yes and No.
 Authorized TimeStamps
Update
Select Yes to load a factory default dbt or No to load from a file on an external media.
Append
Select Yes to add the dbt from the manufacturer's defaults list to the existing dbt. Select
No to load the dbt from a file. The options are Yes and No.

OsRecovery Signatures
Update
Select Yes to load a factory default dbr or No to load from a file on an external media.
Append
Select Yes to add the dbr from the manufacturer's defaults list to the existing dbr. Select
No to load the dbr from a file. The options are Yes and No.
111
Chapter 6: UEFI BIOS