[U-Boot] Having problem Booting linux from nand flash

[Peter Pan]

Dear Wolfgang Denk:
I'm using U-Boot-2009-08 now. And I have a problem booting
my linux image from nand flash. I can boot from my norflash
using NFS, and mount my Nand flash, nand flash works file with
fstype yaffs2.
I run command nboot 800000 0 0 (device 0, offset 0, into memory
0x800000), then it prints out my image information and then says
that it reads failed. The prints are:
-----------------------------------------------------------------
Loading from NAND 1GiB 3,3V 8-bit, offset 0x0
   Image Name:   Linux-2.6.22.sac.rd
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
   Data Size:    1045865 Bytes = 1021.4 kB
   Load Address: 00000000
   Entry Point:  00000000
NAND read from offset ffffffff failed 0
** Read error
-----------------------------------------------------------------
This seems that all the blocks are bad blocks, so I try "nand bad",
there are no bad blocks in my nand flash as it says.
    Then, I look into the source, and find something strange. In
function "nand_load_image" in /common/cmd_nand.c, I print out the
parameters of function "nand_load_image" gives "nand_read_skip_bad"
and function "nand_read_skip_bad" gets, they are different.
-----------------------------------------------------------------
nand = 0xfffdab8, offset = 0x0, &cnt = 0xfba1768. addr = 0x800000 in
nand_load_image.
nand = 0xfffdab8, offset = 0x0, length = 0x0, buffer = 0xfba1768 in
nand_read_skip_bad.
-----------------------------------------------------------------
This seems the stack is wrong?  I don't know what to do next now.