hi kader,
please, can you attach your backup of mtd0 here?

since the above
set updt_boot "vfd LD;tftp 0x80000000 u-boot.bin;nand erase 0x00000000 0x00040000;nand write.jffs2 0x80000000 0x00000000 $filesize;vfd _End"
needs a formatted jffs2 filesystem and furthermore loads via tftp im not sure if that will work. The backup of the original mtd0 should show us the needed information