Just don't be in a hurry when you do the move. If the 211 you are connecting to didn't have a drive connected previously, once it detects the drive it will want to download the software to support the EHD then reboot then download the guide information. Then when you unplug the drive it will want to download the software to convert itself back to a non EHD connected 211, reboot and then download the guide.
Same thing with the 211 you removed it from. Allow 10 -15 minutes for the process each time you make the change and /or switch a drive between two 211 receivers.
I didn't even know this was possible. I know on the 622/722/612 it's not allowed. You'll get a message that the drive is already being used with a different receiver. Unless of course something has changed.