Thanks for the help. I'm getting an error when I try to write my data to the chip. The error appears as follows: "Write...Error at:04F00:(D0)" What does it mean? Is there something wrong with my code or is the chip writer not set up correctly? The chip I copied the data from is an M5M27C256AK Mitsubishi e931/Motorola . its automotive in a 92 turbo car and the chip I'm attempting to write to is an SST27SF256. please help thanks you guys