In my case, definitely a hardware defect in the phone. Best Buy refused to replace it, even after replicating the issue in front of them. I have the black tie replacement insurance, and they told me they would have to send it off! They insisted a software update would fix it (which it didn't). Sprint sent me a brand new unit, and low an behold, no bluetooth disconnecting issues with wifi on...All of you with the issue I had, get a replacement phone, as it's junk hardware!