I have used many ways to recover . here http://www.techyv.com/questions/how-remove-write-protection-flash-drive, here http://kb.sandisk.com/app/answers/detail/a_id/5232/~/return-material-authorization-(rma)-process ~~> I’m in Vietnam
I can not find the firmware of this type of usb, I believe that if I find it I can fix it