Sergey Kubushyn wrote:
> OK, please explain how can one mount _ROOT_ filesystem with "mount -t". Try
> to explain where that "mount" comes from if the root FS is not mounted.
> Just to counter a possible excuse and to avoid emailing twice - you do NOT
> mount a _ROOT_ YAFFS (or ext2 or whatever it is) filesystem when booting
> with initrd. That's initrd that contains a root filesystem. You mount the
> other filesystem elsewhere and only then you pivot_root() to it.
> 
> There is only one way to mount the root filesystem. And there is no way to
> tell "-t yaffs2" to the kernel. At least without some unconventional
> trickery.

The kernel supports forcing a root filesystem type, using the
"rootfstype" kernel parameter, so something like "rootfstype=yaffs" will
  ensure that you get the one you're after.

Normally this is a good idea anyway, as it avoids the error messages
that the other filesystems emit when they fail to mount your mtd device.

Andre