A method of fabricating ROM products through the use of embedded flash/EEPROM prototypes is disclosed. This is accomplished by first forming a Flash/EEPROM prototype, performing programming simulations on the prototype, developing a ROM code and mask, and then forming a ROM product in the same manufacturing line by skipping certain Flash/EEPROM steps and then implanting the ROM code into the final ROM product. The method improves turn-around-time in the manufacturing line, and reduces cost to the customer. A method of doing business is also disclosed directed to providing ROM products to a customer without much redesign time and effort on the part of the customer.