Our S5 has Wifi greyed out since 5.2.8.
Today I tried to update to 5.2.11 using USB, but this gives me an error "The firmware has failed to verify, Please retry installation."
Downloaded the firmware again, tried to install 5.2.11, the same message appears.
Reset the printer to factory, tried to install 5.2.11, the same message appears.
Reset Cura Connect, tried to install 5.2.11, the same message appears.
I'm using the USB stick supplied with the printer.