Hi, I have 2 projects: a boot loader and a user program. The boot loader provides serveral C functions a user program can use. The address of these functions and its parameters are known. When compiling the user program the compiler has no access to the source code of the boot loader. So I have problems to tell the compiler where the functions are located. They are outside of the code range of the user program. The only solution I have found so far is to declare them a second time with an assembler LJMP. Isn't there a C solution to declare an extern function at a certain location, with out having an empty body at this location? TIA Bernhard Gustl Bauer