How to tell if you need a PassKey or PassKey2:

1. Insert a DS game in the NDS slot.
2. Turn on your DS (Hold START for boot menu) and open Pictochat, select a room.
3. Now remove the NDS cartridge from the NDS slot (don't worry, you can't do much harm).
4. Both screens should turn the same color.

If the screens DON'T turn YELLOW (and you're not using iQue DS), it is a safe bet that it's PassKey compatible. You can also use PassKey2.

If the screens DO turn YELLOW, that means you'll need PassKey2 for the M3 to work in NDS mode.

NDS firmware color 'chart':

- FW1: DS will freeze, when you remove the cart.
- FW2: Grayish Blue
- FW3: Dark Green (Note! A silver DS bought in MK:DS bundle is most probably NOT installed with FW4!)
- FW4: Yellow
- FW5: Magenta
- iQue FW: Dark Green
- FlashME: Dark Green