To use the Sbooster with my Lumin T2, I needed to open the case, disconnect the internal power supply, and cut a wire (although I supposed I could have desoldered it), then connect their PS to the motherboard. I presume the procedure would be the same for a U2 Mini.
Why on earth would Lumin honor a warranty after somebody permanently modified their device?
If you replaced your new car's transmission with an aftermarket transmission would you expect the car's manufacturer to respect your warranty?