Yamaha Cd S303 Firmware Update Guide

This resolves 90% of erratic behavior, including disc reading errors and display glitches. It costs nothing and takes 10 seconds.

If the "UPGRADE" message remains for longer than a minute, the update process has likely failed. In this case, turn off the unit and remove the USB flash drive. Double-check that you have followed the preparation steps correctly: the firmware file must be in the USB root folder, and its filename must not have been changed. Once you have verified this, start the update procedure again from the beginning. Yamaha Cd S303 Firmware Update