I was playing with this as well a few months ago, I was trying to flip the removable bit on my flash drive so that I could partition it and make the second partition visible under windows. Turns out that alot of drives have this "removable" bit in the firmware someplace, and only some of them can be flipped. I ruined a 16GB flash drive doing this lol. I'm not sure exactly what happened to it, because it would fail to reformat, and windows would only detect the drive if you disabled it in device manger and the re enabled it.
I tried checking the drive's file system layout with a hex editor and it all appeared to be okay, so using one of those utilities must have damaged the actual controller or firmware of the drive.
I tried checking the drive's file system layout with a hex editor and it all appeared to be okay, so using one of those utilities must have damaged the actual controller or firmware of the drive.