[…]In 2017, we released our first public whitepaper describing the philosophy and implementation of the Qualcomm Technologies’ Secure Boot solution. Since then, the solution has been improved and we are pleased to make available a new release of the “Secure Boot and Image Authentication” technical overview whitepaper.[…]
https://www.qualcomm.com/news/onq/2019/08/21/secure-boot-and-image-authentication-improvements
https://www.qualcomm.com/documents/secure-boot-and-image-authentication-technical-overview-v20
Firmware Security 