You can try the following things:
Reinstall the driver - Go to Device Manager > locate the device > Uninstall device > Then Scan for hardware changes. It should reinstall it.
Plug it in other spare computer if you can and install iCUE in it - It may seen stupid but I once had a firmware problem with my keyboard and mouse (also from Corsair) and force update was always failing, I plug them in other computer I had, and the firmware install went fine.
If none of this works RMA it, probably you have a defective unit.