How to reset write protection?
My flash is suddenly write protected
How can I recover it?
your USB flash drive is probably over it's lifetime. Each USB flash drive has limited count of maximum writes and after that the flash remains in read only state.
It means that you can copy data out but you are not able to write any data on the stick - this is pretty cool because you can safely move your data out without any data loss (reading is not limited).
It's time to buy the new USB flash stick dude!