The importance of hardening robotic and autonomous systems (RAS) considered for field deployment against cyber threats has been recognized by organizations across the Department of Defense (DoD). Among these needs is the ability to securely provide these modern military vehicles with software updates containing critical new functionality and security improvements. A secure update process and system for military RAS has been implemented building on a framework designed for the automotive industry. Demonstrations of the capabilities and mitigations against possible attacks on the update process will be performed on a RAS MRZR in a mock field environment.