Reverse engineered library from Atmel AVR116 application notes, will help to better understand they flash layer translation technology. Project provide example of using this library over virtual flash device and FatFS from Chan. You can build example with VisualStudio 2013 and also you can use FTL source with your favorite MCU ( i tested it on my STM32 dev board ). You can use it only for education purpose, i checked internal logic with original library but you must understand what something can goes wrong ;)
Project fully compatible with original AVR library on binary level, that means what you can work with AVR libs to create FTL on flash device and then continue using already formatted flash with my code or vise versa.