1. use mt manager to open the cool music apk to find the installation package, and click view.

2. click the classes.dex file.

3. click on the dex editor.

4. Click on the top right corner to search for the constant hasBought.

5. Click on the top right corner, and select constant search hasBought (meaning bought). There are two files, and both hasBought should be modified.

6. open hasbought, and add const4v1returnv in the first line (there are two hasboughts to be modified).