[Yaffs] Is YAFFS2 support required in boot loader?

Hi all!

I am having four partiton on NAND flash: boot, environment variable, kernel
image and root FS ( YAFFS2) and boot loader needs to download kernel image
and root FS using TFTP / FTP. How kernel image and root FS can be converted
into YAFFS format and downloaded? What support I need to provide in boot
loader?

Thanks,
Rakhi