On my K60-based custom board I added the MSD Host Bootloader porting the AN4368 source code.
The USB Host Bootloader is working properly, but I have an issue relating to USB memory sticks with size 4GB and over: the image.S19 file is found only on about 25% of different memory sticks with that size. However, the device attachment and detachment is always properly detected by the bootloader.
MS Windows formats those memory sticks with FAT32 by default and FAT32 should be the FAT type supported by the bootloader's file system.
Since I get no issue with USB memory sticks with size less than 4GB (2GB, 1GB, ... up to an old 32MB memory stick!!!), that MS Windows formats with FAT by default, I have tried to format the 4GB or 8GB memory sticks with FAT: but I get the same issue.
Since it is now difficult to buy new USB memory sticks with size less than 4GB, my issue's severity has become very high for my application.
Is it a bootloader file-system issue?