[Yaffs] use yaffs

Hi,

I've a s3c2410 board and I mount on NAND yaffs fs, with this
operation:

mkyaffs /dev/mtdN
mount -t yaffs /dev/mtdblockN /mnt/yaffs

with N: number of device.

Is it corretct?

For benchmarking NAND, I use bonnie++. When I use bonnie++
on NAND with YAFFS, it return this errors:

can't putc() - disk full?
nand_write_oob: Failed write verify, page 0x0001ffc0
nand_write_oob: Failed write verify, page 0x0001ffc1

But, when I'm writing on NAND I don't receive any errors.
Why?

Thanks.