Installation instructions:
1. Ensure the Graphcore Linux PCIe driver (kernel module) version 1.2.1 has been installed.
2. Source the enable.sh script in the Graphcore Command Line Tools package (version 1.2.1).
3. Run the Python script:
   $ python3 c600_icu_update_2.6.8.py
   This will guide you through the firmware update process.