How do I reset the MMI system on an Audi A2?

I recently bought a used Audi A2 and the MMI system seems to not be functioning properly. How can I reset it to its default settings?

First, turn off the car and remove the key from the ignition. Then press and hold the control button and turn the ignition on. After the MMI screen turns on, release the control button and press the return button, followed by the car button. This should reset the MMI system.

To reset the MMI system on an Audi A2, locate the MMI control unit in the trunk and disconnect the positive terminal of the battery for about 15 minutes. Reconnect the battery and the system should reset.