if your mtd partitions are well defined in uboot envirenment, you can see the uboot nand partition as this
root@sheeva:~#cat /proc/mtd
dev: size erasesize name
mtd0: 00100000 00020000 "uboot"
mtd1: 00400000 00020000 "uImage"
mtd2: 1ef00000 00020000 "rootfs"
mtd3: 00c00000 00020000 "debian"
root@sheeva:~#
The important thing is to see if a "uboot" named partition exists and its position is "0" (Sizes and addresses are not relevant)
If yes, type this :
root@sheeva:~#grep -a --null-data U-Boot /dev/mtd0ro | cut -d'I' -f1 | grep -a Marvell
U-Boot 1.1.4 (Jul 14 2009 - 06:46:57) Marvell version: 3.4.16
root@sheeva:~#