[cluckindan]

Flash worm into device and RMA it. Boom.

[federiconafria]

Just flash it in a shop and someone will send it back.

[trashb]

Make sure the new firmware slightly corrupts the audio for guaranteed high return rate.

To be extra malicious, if you can infect a connected pc make it propagate the worm to any similar device plugged into the pc over usb in the future.