Try the 1.21RC5 files. Copy Duet2CombinedFirmware.bin and DuetWiFiServer.bin to /sys, restart the Duet, send M997 S0 and when the main firmware has installed, send M997 S1. You don't need ReprapFirmware.bin, that is for older Duets. Also DuetWebControl.zip needs to be either uploaded via DWC or unzipped to /www - easiest is to upload it via DWC when you have the web interface working again.
