Design of complex embedded software requires ingenious solutions to many architectural problems. One such solution that would be a crucial catalyst in designing scalable and customized embedded software, is developed by API (Application Programming Interface) level simulator. The use of API level simulator has been gaining wide acceptance due to its design and verification efficiency by enabling parallel development in multiple software layers. However, there are two major bottlenecks in realizing practical systems: source code modification and recompilation of the target software. The paper proposes a novel simulation technique to resolve these two critical issues. The proposed technique makes it possible to replace any part of the target binary without modifying its source code and recompiling it.