I'm having some trouble with my rooted Galaxy S4 (SGH-M919). It'll just shut down out of nowhere, doesn't matter if it's sitting on a table or in use. I wasn't sure what was causing it, but I figured out it has something to do with the SD Card (I think). The phone would shut down literally every 2 minutes for the past few days. So, I took out the SD Card to take stuff off of there, and thought maybe I'll just run the phone without it for a while. Well, it stayed on for about 18 hours with no problem. I popped the SD card back in, and within 2 minutes it shut down on it's own. So, it's a problem with the SD Card obviously, but the question is what? The actual card, or the SD Card reader on the phone? Is there any way to figure that out short of buying a new SD card, or bringing it into have someone look at the hardware?