Duo
A white clamshell handheld for your iPhone. Two screens, buttons that click back, a touch screen on the bottom, and the .nds games you already own.
What Duo is
- Two screens, a D-pad, A/B/X/Y, L/R, START and SELECT, and a touch screen you can play with a fingertip or a stylus.
- Plays the .nds game files you own, imported from the Files app, AirDrop or “Open in”. No games are included, and Duo never downloads or finds games for you.
- On iPhone Duo it fills the inner display. Fold the phone to close the lid; unfold it to play on. Turn it and Duo turns with you.
- Every on-screen button clicks with haptics, and games with rumble support shake your phone and your controller.
- Game controllers and hardware keyboards work out of the box. No BIOS or firmware files needed.
- Comes with the DUO Demo, a doodle pad we made ourselves. Play it free before you unlock Duo, and any time after.
- No accounts, no ads, no tracking. Your games and saves stay on your device.
Questions
How do I add a game?
On the menu, tap the card slot and pick your .nds file in Files. You can also AirDrop a file to your phone, or use “Open in” from another app and choose Duo.
Files you copy into On My iPhone › Duo › Games in the Files app show up on the menu too.
Duo doesn’t include or find games. Please only import games you have the right to play.
Does Duo come with any games?
Just one: the DUO Demo, a doodle pad we made ourselves. Everything else is yours to bring.
Can I try Duo before paying?
Yes. Setup ends with a free test drive on the DUO Demo: draw on the touch screen, feel the buttons click and hold A for rumble. Press START when you’re done. You can play it again any time from the Unlock screen.
Duo Pass also starts with a 3-day free trial, so you can play your own games before you’re charged.
How do saves work?
Automatically. When a game saves, Duo writes it to On My iPhone › Duo › Saves about half a second later.
Closing the lid or leaving the app also sets a resume point, so you come back to the exact moment you left.
To back up, copy the Saves folder anywhere you like. Deleting Duo deletes its folder, saves included, so copy them out first.
What happens when I close the lid?
The game goes to sleep and its save and resume point are written. On iPhone Duo, folding the phone closes the lid. On other iPhones, leaving the app does. Open it again and the game wakes up.
To switch the console off and go back to the menu, hold the green power light on the hinge for one second.
Do I need a BIOS or firmware files?
No. Duo uses melonDS’s open-source replacement BIOS, so there’s nothing extra to add.
Which controllers and keyboards work?
Bluetooth game controllers that pair with your iPhone (Settings › Bluetooth) and hardware keyboards. Controller buttons map by position, so the right-hand face button is A.
| Button | Keyboard | Controller |
|---|---|---|
| D-pad | Arrow keys | D-pad or left stick |
| A B X Y | X Z S A | Face buttons |
| L R | Q W | Shoulders and triggers |
| START | Return | Menu |
| SELECT | Right Shift or Delete | Options |
How do I restore my purchase?
Open Duo and, on the Unlock screen that follows setup, tap Restore. Use the same Apple Account you bought with.
Duo Lifetime supports Family Sharing, so people in your family group can restore it on their own devices.
How do I cancel Duo Pass?
Open Settings › your name › Subscriptions › Duo and tap Cancel Subscription. You can also get there from your account in the App Store.
Cancel at least 24 hours before your trial or current year ends to avoid the next charge. You keep Duo until the end of the period you paid for. Deleting the app doesn’t cancel the subscription.
Can I get a refund?
Apple handles all payments, so refunds go through Apple. Request one at reportaproblem.apple.com.
Does Duo collect my data?
Barely. No accounts, no ads, no tracking. Your games, saves and settings stay on your device; only an anonymous record of your App Store purchase is sent, so we can count sales. Read the privacy policy.
Still stuck?
Write to duo@jurre.me. Tell us your device, its iOS version and what happened, and we’ll get back to you.