A computing system for a secure and reliable firmware update through a verification process, dynamic validation and continuous monitoring for error or failure and speedy correction of Internet of Things (IoT) device operability. The invention uses a Trusted Execution Environment (TEE) for hardware-based isolation of the firmware update, validation and continuous monitoring services. The isolation is performed by hardware System on a Chip (SoC) Security Extensions such as ARM TrustZone or similar technologies on other hardware platforms. The invention therefore comprises Firmware Update Service (FUS), System Validation Service (SMS) and Continuous Monitoring Service (CMS) running in the TEE with dedicated memory and storage, thus providing a trusted configuration management functionality for the operating system (OS) code and applications on IoT devices.Services running in the TEE use both direct (hardware level) and indirect (software agents inside main execution environment (MEE)) methods of control of the MEE. Embodiments of the invention apply all updates to a staging (new) execution environment (SEE) without changing of the MEE.