You have a one time exchange, so getting a new one is no problem. However, think about this. If the only issue is a speck of dust, why bring it back if everything else is fine. U run the risk of getting one with even more problems. Plus dust under the screen is very common with HTC, so chances are you could get another with the same exact issue. Don't forget, you have a year warranty, so if it gets really bad down the Line, or if you drop it and scratch it 3 months from now, your just a phone call away from calling customer care, giving them some crazy story about dropped calls, and bammm, they'll send u out another one. Which by the way, the ones they send out are like triple tested , and usually never have any issues.