Is it as simple as changing the root_dev info? (init and linuxrc)

If I created a partition on mmc for kernel, it seems like it would work, is there something I am not thinking of?

root_dev=mtdblock4
root_dev_name="Flash"
root_fstype="jffs2"
root_fsoptions="rpsize=1024,rpuid=0,rpuid=30000"

You got anything you want to try, you just let me know


EDIT
Now that I think about that, mtdblock4 is rootfs right, so would you need to put something on the kernel device to redirect it, or you need to hack the xloader?