Requires iOS 5.0 or higher
and Siri capability
New commands for Siri - reboot, power off, restart SpringBoard, and enter Safe Mode. Requires a device that has Siri.
You can now launch any app with your voice. Stock apps, all third party apps, and even webclips, just say "open" or "launch" followed by the app's name on your homescreen
Note: This is a Mobile Substrate tweak. No settings are available, and no icon is added to the home screen. Simply install, respring, and use.