In order to upgrade CS64US firmware, you need to use Hotkeys to invoke ""firmware upgrade mode"" as below : (please note your keyboard needs to be plugged into CS64US keyboard console port) 1. Press and hold down [Num Lock] 2. Press and release [-] 3. Release [Num Lock] (The ""Scroll Lock"" and ""Number Lock"" LEDs start blinking) 4. Type [u][p][g][r][a][d][e] 5. Press [Enter] (The CS64US LEDs should be blinking) 6. Then run the Firmware upgrade software http://www.aten.com/download/download_fw.phpNote: While the switch is in Firmware Upgrade Mode, normal keyboard,mouse and video functions are suspended, you will have to connect monitor keyboard and mouse on your computer to run the software.