+@section Related binaries
+
+@subsection qemu-nbd --partition (since 4.0.0)
+
+The ``qemu-nbd --partition $digit'' code (also spelled @option{-P})
+can only handle MBR partitions, and has never correctly handled
+logical partitions beyond partition 5. If you know the offset and
+length of the partition (perhaps by using @code{sfdisk} within the
+guest), you can achieve the effect of exporting just that subset of
+the disk by use of the @option{--image-opts} option with a raw
+blockdev using the @code{offset} and @code{size} parameters layered on
+top of any other existing blockdev. For example, if partition 1 is
+100MiB long starting at 1MiB, the old command:
+
+@code{qemu-nbd -t -P 1 -f qcow2 file.qcow2}
+
+can be rewritten as:
+
+@code{qemu-nbd -t --image-opts driver=raw,offset=1M,size=100M,file.driver=qcow2,file.backing.driver=file,file.backing.filename=file.qcow2}
+
+Alternatively, the @code{nbdkit} project provides a more powerful
+partition filter on top of its nbd plugin, which can be used to select
+an arbitrary MBR or GPT partition on top of any other full-image NBD
+export. Using this to rewrite the above example results in: