Microwave for a minute at 500W without covering. Take it out, then put back in the microwave and for another minute at 500W. Take it out again, toss it around with your hands, and microwave for 30 seconds at 500W. Take it out again and see how it looks, then if needed, microwave for another 30 seconds. The bread is usually pretty dry before the last 30 seconds, so only microwave that last time if necessary. Once the bread is crunchy, it's done.