> Can you please provide more info on that starting from what kernel version you've intergrated yaffs into, whether it's yaffs or yaffs2, what ECC (yaffs or MTD/nand) you're using, what are the NAND flash credentials and so on.

Sure, I integrated it into kernel version 2.6.11. It's yaffs using MTD 
ECC. The flash part that I'm using a K9F1208U0B(64MB, 512 byte per page) 
from Samsung.

Using "nanddump" and u-bootloader "nand read" , I verified that the data 
0xA00 and above are the same. However,u-bootloader's "nand read" 
reading bytes offset from 0 to 0x9FF gets "Failed ECC read".

"nand read 10000 0 200": read from nand offset <0x0> size 0x200 bytes to 
physical location 0x10000

Question: Why is it that ECC is not used for these particular bytes? or 
is it something else I got wrong?

Thanks,
-puker