+ For FIT image, The configuration specification can be
+ appended to the file name, with the format:
+ <path>#<conf>[#<extra-conf[#...]]
+ It will passed to bootm with that address.
+ (see: doc/uImage.FIT/command_syntax_extensions.txt)
+ It useful for overlay selection in pxe file
+ (see: doc/uImage.FIT/overlay-fdt-boot.txt)