Open Remote Config UI -> $ java -jar RemoteConfigUI.jar
Select target device from list
Using menus, Action -> TFTP On/Off, confirm On.
Using menus, Run -> TFTP Client
Use "Select uImage" button to select the firmware to upload
Use "TFTP put" button to upload firmware
If success, text will turn green.
Using menus, Action -> TFTP On/Off, confirm Off (firmware is now written to SPI flash)
Right click on device, or use menus Action -> Reboot to start the new firmware.