I spoke with Siliconera reader Aoshi00 who owns a Japanese Xbox 360 and recently purchased a 120GB hard drive from the US. Before installing the drive he planned to transfer the data over with an official Microsoft hard drive data transfer kit. Unfortunately, the hard drive transfer disc bundled with the cable is region locked for North American consoles only.
We know Microsoft has the ability to region lock or not region lock discs, which makes locking an essential disc an awkward choice. I suppose there aren’t many people sitting around with imported an Xbox 360 so this probably doesn’t affect many. However, if this news is relevant to you, take this information as a warning before you purchase the necessary equipment for a hardware upgrade and make sure you thank Aoshi00 for sharing this with us.