I deleted the OS to try to install version 3.1 and ndless, and it still wouldn't let me downgrade. But when I tried to put 3.2.3 back onto the device, it said that I couldn't install a version of the OS the is older than the currently installed version, which doesn't make sense because there isn't an OS installed and the OS I am trying to install is the newest version there is. Now the calculator just is at a screen that says "Operating system not found. Install OS now." Please help me!