The DCO, Device Configuation Overlay, poses problems for some in computer forensics industry. For most its not relevant, as they are not concerned with this probability of this occuring, e.g .those in electronic discovery.
But, for those who are concered about the DCO it poses a problem. EnCase, FTK, or Linen, cannot image sectors hidden by the DCO. No, purely software based imaging tool (currently available) can.
So, how can you image the DCO?
The best method to access the DCO simply and without specialist knowledge of hard drives, is using a cloner. The Logicube Talon or Quest, as well as the ICS Solo3 are all capable of accessing the HPA and DCO, automatically.