Sorry if this issue has already been addressed, but I've searched the forums here and could find any help. Anyhow, I have a sprint 8130 phone and a SanDisk 512mb micro sd card. From time to time when I plug the Blackberry into my Mac and enable the mass storage feature, about 10 seconds later a message will pop up on the computer saying that the device was removed improperly. My blackberry goes blank and I have to pull the battery to bring it "back to life". This doesn't happen all of the time but I find it happening more frequently now.
First of all why only 512 mb should get aleast a gig. Have you removed the sd card and battery pull? Well thats what I would do first and see what happens, Should be ok after that.