Typically on its next connection, after the guided setup connections are done.
You could force about 4 Tivo connections, then it will get a software update, reboot to start its software. After that 1 more for the guide data for the upcoming weeks.
TiVo HD 1TB (157 HD Hrs, PLS, "S3HD")
Roamio, Oh Roamio!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!