You could try to list the flash partition:
mtd0 is usually the physical flash and mtd1, mtd2 etc.. the partition.
If you have mtd1, you can format and mount the partition, for example:
mount -t jffs2 /dev/mtdblock3 /mnt/flash
Then edit the startup script (check /etc/inittab to locate it) to mount the partition at boot time and run your program.