mtd-utils error on micro2440-128M

I have a micro2440-128M, and there is /dev/mtd0 (bootloader), mtd1
(kernel), mtd2(yaffs2), and mtd3(whole NAND flash). When I try to read any
of the mtd device (mtd0, mtd1 ,etc), either using "cat" directly or using
the mtd_debug read tool, I would get a lot of "uncorrectable error". The
device itself works fine. 

Has any of you got mtd-utils working on a 128M mini/micro 2440 board with
friendlyarm kernel and roofs? I know you can use bootloader to do some of
the flash work, but I would like to be able to upgrade kernel and
bootloader within a booted system.

Your help is appreciated.