EasyIAP™ is a boot-strap loader (BSL) software that enables SST FlashFlex customers to download/upload their application software into/from the FlashFlex flash memory via In-Application Programming (IAP) while their system is running. Important features are: data download/upload, self-detection of the serial connection, and automatic reset after download. This BSL example has been pre-programmed into production revision CA or later of the SST89C5x products and thus is ready to support downloading new user application software, either on the production line or in the field. The source code of the MCU firmware is provided to SST customers free of charge as a reference example so that designers can choose to use the pre-programmed code in its original form or tailor it to their own FlashFlex application. The MCU source code is intentionally well-documented in order to guide designers to more easily understand the firmware example.