In embedded software development, the programming language C and inline assembly code are traditionally widely used. However, tools for C program-understanding, e.g., cross-referencers or call graph extractors, are not mature still today. In this paper, we introduce a novel technique for developing program-understanding tools, based on binary-level lightweight data integration. To verify this diea, we first propose a new markup language for DWARF2 debugging information, and then, using the technique, we experimentally developed two cross-referencers (called dxref and rxref) and a call graph extractor (called bscg) for C. Our preliminary evaluation shows that the technique enabled us to efficiently develop practical and flexible tools.