The XNAND access is implemented in userspace in conjunction with NBD (network block device). You may want to refer to the nandctl page which will show more advanced usage, but by default the linuxrc script will mount the sd card with the following layout.
/dev/nbd0 - whole disk device of XNAND drive /dev/nbd1 - 1st partition (kernel partition) /dev/nbd2 - 2nd partition (EXT2 initrd) /dev/nbd3 - 3rd partition (252MByte mini Debian EXT3 filesystem) /dev/nbd4 - 4th partition (unused)
|Note:||NBD devices do not report size correctly. If you are formatting a partition or using dd you will need to specify the size.|