I will unfortunately not be able to give you a solution for your problem but still giving two advises:
- It has been reported by a couple of people that the TV USB is not an appropriate (not enough power) power source for the PI.
- Why are you going thru all this hassle of turning off/on the Pi at all? The power consumption is minimal and you risk with your power on/off that one day you do a unclean unmount and you get filesystem issues.