I believe there was a change made recently that would facilitate NOT including the YAFFS unless it was explicitely required. THis was to help customers who felt that the image was getting too large. I believe what you’ll need to do is look in the bsp_fs.h file that is associated with your project. At the bottom is a macro entitled BSP_YAFFS_DRIVER_ENABLE. I believe by default this is defined to FALSE. Set this to TRUE. Then clean and refresh your project and then rebuild.