Action Replay Duo Compatibility – DS/DSi/3DS Game Cards (No – GBA/DS Phat/Lite Only)

No. The Action Replay Duo is designed exclusively for:

• Game Boy Advance (GBA) cartridges (Slot 2 on DS Phat/Lite).
• Original Nintendo DS game cards (Slot 1) — only on DS Phat/Lite.

Why It Fails on DSi/3DS Games

• Different Cartridge Interface: DSi/3DS cards have extra pins for encryption, larger save chips, and DSi-mode CPU access. The Duo's hardware cannot communicate with them.
• Slot Mismatch: Duo plugs into GBA slot (Slot 2). DSi/3DS lack Slot 2 entirely.
• Software Incompatibility: Duo's firmware only recognizes GBA/DS (NTR) ROM headers, not TWL (DSi) or CTR (3DS) formats.

Alternatives for DSi/3DS Cheating

• Action Replay DSi / 3DS: Separate hardware (blue cartridge) for DSi/3DS games. Discontinued; used only.
• CFW + Cheat Plugins: Luma3DS + Rosalina menu + cheats.txt (3DS); TWiLight Menu++ + .cht files (DSi/3DS). Free, active, more powerful.

The Duo is a GBA/DS Phat/Lite tool only. It cannot touch DSi-enhanced or 3DS titles.