I recently used UNetBootin to install Linux Mint Live on a 2GB flash drive. However, I think the OS thinks it's a CD, and doesn't make any changes. If I install software, change settings, etc, it just erases them when I reboot (OS loaded to RAM). I'm looking for a way to either "tell" it it's a flash drive (and therefore make it writeable), or install the full desktop (not live) version on a flash drive, and still leave the machine's normal Windows HDD alone. I've been told that Live is supposed to work just as a full installation does, but with the option to install it to the computer's storage device. Is this not true? Other distros I've tried work fine, but Mint has this problem, and it seems like the one I want to keep.
The LiveCD's are setup to specifically work with a read only system. When you copied the data via UNetBootin, it merely just made a copy, the only difference is the boot medium. The filesystem and the OS are still designed as if the medium is read-only, whether that is the case or not.
The feature you are looking for is called "Persistence" or "Live CD Persistence", I was able to find a helpful post from a Mint user on the Mint forums on how to create a persistent install.
If you dislike that option your best bet for alternative solutions would probably be: