Hi, I am using an 80C400, I have flash located from (CE3)0x400000 - 0x4FFFFF and RAM located at (CE0) 0x010000 - 0x1FFFFF and (CE1) 0x200000 - 0x3FFFFF. I have an external crystal clocking at 18.432MHz. The problem: If code is written in C51 which resides in flash, and the 80C400 system clock is set for x4 the application will lock due to the slow speed of the flash. It is not possible to put an address latch into the design since the hardware is already built. The system RAM is battery backed, and the battery can be removed from the system at any time. My thought for a solution: Write an application which does not access FLASH at all. Then write a separate loader to reside and operate at clock x1 out of flash. Copy the application code to RAM from flash and then redirect to the application residing in RAM. Questions: How do I get the application into RAM. (VIA a custom serial loader? (Parts cannot be programmed but reside on the PCB)) Are there any examples anyone knows of that are similar to my situation? I have tried using USERCLASSes and segmets with separate C files, massaging hex files and copying code from FLASH to RAM, but so far I have not had consistent results. Thanks for any help anyone can give. Bill