James Clark developed SPEFDS support for the zephyrproject-rtos/trusted-firmware-a repository, enabling access to the PMSDSFR_EL1 register and updating the SPE enable and disable logic to accommodate the FEAT_SPE_FDS hardware feature. His work ensured that secure performance monitoring could operate correctly at NS-EL1 and NS-EL2 privilege levels when the feature is present, improving platform compatibility and reducing risk during hardware bring-up. James applied his expertise in ARM architecture, embedded systems, and system programming using C, focusing on low-level register access and feature-flag logic. The depth of his contribution strengthened secure firmware control for future ARM platforms.