Make sure the source volume you choose when creating a NetRestore image has a Recovery HD partition associated with it.
Some reasons that a volume might lack a Recovery partition:
- It is a software RAID volume. Recovery HD partitions are not supported on software RAID volumes.
- It is a disk image created by Disk Utility from an OS X volume source. Disk Utility effectively removes the Recovery HD partition when creating the image.
- It is a volume created by restoring such an image created by Disk Utility.
- It is a volume created by restoring an image created by System Image Utility with the "include recovery partition" checkbox disabled.
- The Recovery HD partition was manually removed.