Develop and optimize low-level embedded firmware in C++ for avionics systems, flight controllers, and mission payloads, focusing on performance, reliability, and safety-critical applications. Port frameworks and applications to new RTOSes and hardware platforms, create Board Support Packages (BSPs), adapt Hardware Abstraction Layers (HALs), and develop peripheral drivers for interfaces like I2C, SPI, UART, and ADC. Conduct unit and integration testing including fault injection and MISRA C compliance checks, diagnose cross-domain issues across electromechanical, software, networking, and RF subsystems, and collaborate with hardware teams to validate firmware incorporating secure boot, watchdogs, and fault-tolerant designs. Requires 5+ years embedded systems development, U.S. citizenship, ability to obtain DoD security clearance, strong Linux/Windows proficiency, and expertise in Python, Bash, Shell, and C/C++.