Dear list, Has anyone experienced the following problem? I created a program on the ICD using the F877 in the circuit, to emulate a F874. With the ICD in the circuit, everything works well. I change the project to a MPSIM project for the F874, recompile and program it into a F874 via a PICstart Plus, replace the ICD header with a straight 874 and the project is a no-go. Programming it into a F877 works, yet everything is written for a F874. I have not used any special functions of the 877 like shared banks, or higher memory. What is going on? Stephan