If your mp3 player got wet and is now displaying a message saying "firmware upgrade", it is possible that the device is malfunctioning due to water damage.
Here are a few steps you can try to potentially fix the issue:
# Remove the battery and let the device dry completely for at least 24-48 hours.
# Once dry, re-insert the battery and turn on the device. If it still displays the "firmware upgrade" message, try connecting the device to a computer to see if it can be recognized and firmware can be reinstalled.
# If the above steps do not work, it may be necessary to take the device to a professional repair shop or contact the manufacturer for further assistance.
It's important to note that water damage can be difficult to repair and may not be covered under warranty, so it's best to avoid exposing your electronic devices to water whenever possible.