If you are Cloning an image using Thunderbolt and Disk Utility (or even using Firewire instead of Thunderbolt), you may come across this error message:
I've actually never experienced that with Thunderbolt (not saying it can't happen), but I've had it happen twice using Firewire. At first I thought it was the cable ("broken pipe" would indicate to me a patchy physical connection of some kind), so I switched out the cable, and that didn't help. In another situation, I knew the cable was good, because I'd used it several times.
A possible solution
Try switching the direction. So if Mac A is in target disk mode and Mac B is in recovery mode, make it so Mac A is in recovery mode and Mac B is in target disk mode.
I don't know that this is the official workaround/fix or that this will always work, but I've gotten this error twice, and this workaround/fix worked in both cases.