Tilmann Reh wrote:
-------------------------------
before I start writing one from scratch - does anyone know a free & simple tool to merge HEX files?
-------------------------------

I dont know which compiler you use but I came across Bascom $OBJ obj with this directive you can merge the object file into your program that has been written for some specific purpose .

BTW why don't you Reverse compile it and use the Asm codes ? you can actually manuplate these codes the way you like !