2. If using FAT, as Greg suggested, take care of respecting the 8.3 convention name: https://en.wikipedia.org/wiki/8.3_filename#:~:text=An%208.3%20filename%20(also%20called,for%20compatibility%20with%20legacy%20programs .
That should not be necessary, the NuttX FAT supports long file name, mixed upper/lower case, etc. You do not have to limit yourself to 8.3 names.
This is controlled by the configuration. See nuttx/fs/fat/Kconfig
