silly question, but have you peered inside your phone to make sure you didn't damage a contact or some dirt/trash is inside touching the contacts ?

if you're like me you didn't read the directions the first time and assumed it was going to be a regular microsd card and got one of those stuck in there and had to pull it out with a knife...

I also notice alot that my m2 card tends to just "fall out" of my w580i for no reason, check to see if it is getting a firm connection.