The initialization of a computer system including a secure execution mode-capable processor includes storing a secure operating system code segment loader to a plurality of locations corresponding to a particular range of addresses within a system memory. The method also includes executing a security initialization instruction. Executing the security initialization instruction may cause several operations to be performed including transmitting a start transaction including a base address of the particular range of addresses. In addition, executing the security instruction may also cause another operation to be performed including retrieving the secure operating system code segment loader from the system memory and transmitting the secure operating system code segment loader for validation as a plurality of data transactions.