Changing NES Controller Mapping for Super Mario Bros.: Use an Emulator

The original NES cartridge hard-codes controls — no menu, no remap.

On Emulator (PC / Phone / Raspberry Pi)

1. Download Mesen (accuracy), FCEUX (features), or RetroArch (multi-system).
2. Load Super Mario Bros. ROM (dump your own cart).
3. Settings → Input → Remap A/B/Start/Select/D-Pad to keyboard/gamepad.
4. Save profile.

On Real Hardware

• NES Four Score / Satellite — Extra ports, same mapping.
• Controller mods — Internal rewiring (soldering).
• 8BitDo / Retro-Bit wireless adapters — Map via companion app (some support remap).

Emulation is the practical answer.