When carrying out work on the device, proceed as follows:

1. Remove all mobile data carriers (USB sticks, memory cards and so on).

2. Shut down the device.

3. Switch off the device.

4. Unplug the mains cable from the socket.

5. Remove the side panel (If you want to exchange cards, remove the left side panel).

6. Carry out upgrade operations.

7. Attach the side panel again.

8. Put the device into operation again.