hi, i buyed a ti nspire cas touchpad yesterday, after a lot of trouble i upgrade the OS to the 3.1.0.392 version, but there's a lot of problems, every key is switched, i press 2 and the calculator understan a, and the same is for every key, the touchpd doesn't works, do you know a solution?or a way to downgrade the os, even in the reset screen the calculator doesn't recognize the right key