Smoked EFI Live Box
I would say your tuner's EFILive handheld unit is now wrecked, it will need repair.
Also, similar thing can happen when powering the laptop (to which the EFILive handheld is plugged in to) using an inverter connected to vehicle battery, i.e. this causes a ground loop with 2 different ground voltages at each end, so high current flows on the ground and thru the handheld.





