Anyone upgrading to 2.0 from a firmware version prior to 1.21 needs a further piece of information. At version 1.21 the name of the firmware binary for the Duet WiFi and Duet Ethernet was changed to Duet2CombinedFirmware.bin. But if your existing firmware is older than 1.21 then it will expect a different firmware binary filename. So after downloading Duet2CombinedFirmware.bin, you will need to rename it to either DuetWiFiFirmware.bin or DuetEthernetFirmware.bin in order to install it.