There are three ways to tell if your DSTT is a fake: 1) Get the DsttFlashChecker program, install it on your microSD cart, and run it. Sometimes the program can't recognize your chip, in which case you'll have to use one of the other ways (see below)....

The official menu is terribly outdated, and it is highly recommended that you use the unofficial (fake-killer disabled) firmware (see above) which is compatible with far more games. The official menu contains fake-killer firmware, so do NOT install it...

If you're pretty sure that your DSTT wasn't destroyed by fake-killer firmware (if you know yours is real or if you haven't run the official firmware on it), try the steps under "How do I set up my DSTT/microSD card?" If it still doesn't work, your DSTT...