You may need to use WDidle3 and disable the intelli park feature to let it boot up. Only Western Digital drives has this.
Series 2 (80 hrs,PLS, Retired)
TiVo HD 1TB (157 HD Hrs, PLS)
Roamio, Oh Roamio!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!