I'm no expert, but curiosity killed the cat. What I'm saying is, by flipping that polarity, no matter how short of a time for, you definitely fried a power management chip or some part on the voltage regulating circuit. They're designed to work in one way only, yeah they may have tolerances, but they're not much. Think of a zenner diode, they work great in one way, but reverse it, and it breaksdown and is no longer useable. Sadly bud, I think you killed.