The following is a list of components, to illustrate the nature of Trusted Substrate

• SCP-firmware
• TF-A
• OP-TEE
• U-Boot
• StandAloneMM from edk2-platforms
• fTPM

Upcoming support for possible components

• FF-A compatible OPTEE (at least one SPM can exist in pre 8.4 arm architectures
• PKCS#11 API's
• SCMI server
• OPTEE TAs
• FIDO onboarding agent
• trust features