What is secure boot?
Secure boot ensures only authenticated software runs on the device and is achieved by verifying digital signatures of the software prior to executing that code. To achieve secure boot, processor/SoC support is required. In our experience, some of the more secure boot friendly processors with readily available documentation are NXP i.MX/QorIQ Layerscape, Xilinx Zynq, Atmel SAMA5, TI Sitara and Qualcomm Snapdragon series. Some TI Sitara processors (AM335x) might involve TI factory programming of signing keys and custom part numbers.