Like Merco says, I usually remove the XQD card then just use the SD card in the card reader and camera. I always reformat the SD card before using it to make sure it is completely empty. Replace XQD card once update has completed.
Also, when updating firmware, make sure your camera battery is min 80% full, else the update wont happen. I spent 1/2 a day trying to update before finding out that the camera wont do this on a low battery.
- stevev likes this