Reading data from NAND FLASH without ECC is not recommended

[Polyakov Artem]

Hi all! Sorry for my poor english.
I want to ask - why by default reading from NAND flash provided without
ECC?
I work with Samsung K9F5608U0С 32M flash.
And one interest thing for me is that debug messages show that oob bytes
for ECC are used by system. I mean, after eraseing - all bytes are 0xFF.
But my debug messages shows this:
> write oob(00001890): 65 55 97 5a ffff 69 57 ff ff ff ff ff ff ff ff
bytes for ECC are not equal 0xFF!
but system dont use this bytes for ECC correction:
> Reading data from NAND FLASH without ECC is not recommended