I got stucked while upgrading the Wireless Light Control System from Dresden Elektronik through the web interface. The deCONZ software just closed when I invoked an update.

To work with this issue, one can just start the upgrade process manual via CLI. I write it down here, as I haven´t found it documented anywhere else.

1. Log in to the Raspberry Pi via SSH
2. Goto  /usr/bin
3. Start the upgrade process via:  sudo ./deCONZ-update.sh

The updater will download new firmware files from the dereseden elektronik homepage and flash them directly via GCFFlasher to your system. I am now running on 2.02.05 firmware version.