DO-254 is a recent challenge facing aerospace companies, and in some cases, companies serving other safety- and mission-critical markets. HDL design falls under the DO-254 lifecycle category “Detailed Design.” This paper describes the DO-254 compliance considerations for HDL coding and Detailed Design as well as other related processes. It also introduces a tool that supports HDL code development and assists with several other key aspects of DO-254 compliance, simplifying the process and bringing down the costs of these notoriously expensive programs.