I'm not sure which TC release you run during this time. Example : TC5.1
In TC5.1 the following method will be used to factory defaulting the systems:
• When the unit is off, press and hold the power button
• Wait until the power LED goes dark and then light up again (approximately 10 seconds).
• Then release the power button and press it twice.
• The system will boot up and display a confirmation message on the video screen if the
process was successful.
If you run othe release, please check out the release notes on CCO.