Hello. I have a USB stick. It seems to be partitioned into two. One of which I can read, write and format at will, the other one is read only. It doesn't show up in disk utility but always mounts when I plug it in. When I try to erase it in the terminal I get "Error: -69877: Couldn't open device". It is under the CD Partition Scheme. Any ideas on how I can format the whole thing? Thanks.