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How to Fix Bugged Default NES Gamepad Input in Nestopia on Debian 12

  • Fix the bugged default NES gamepad input in Nestopia on Debian 12 by remapping the buttons in the emulator settings or using a custom configuration file.
  • The article explains what causes this problem and how to change other input settings in Nestopia.
  • The article also explains why the problem occurs and how to avoid it in the future by using a different emulator or controller.

If you are a fan of retro gaming, you may have tried to play some classic NES games on your Debian 12 system using Nestopia, a portable NES/Famicom emulator. However, you may have encountered a frustrating problem: the default NES gamepad input is bugged and does not match the physical buttons on your controller. For example, when you play Super Mario Bros., you may find that the physical B button is mapped to A in the game, and vice versa. This can make the game very hard to play and enjoy.

In this article, we will show you how to fix this problem by remapping the NES gamepad input in Nestopia. We will also explain why this problem occurs and how to avoid it in the future. Finally, we will answer some frequently asked questions related to this topic.

Why is the Default NES Gamepad Input Bugged in Nestopia?

The reason why the default NES gamepad input is bugged in Nestopia is because of a mismatch between the logical and physical layout of the buttons on the NES controller and your PC controller. The NES controller has two main buttons: A and B. The A button is on the right side of the controller, while the B button is on the left side. The PC controller, on the other hand, has four main buttons: A, B, X, and Y. The A button is on the bottom right of the controller, while the B button is on the bottom left. The X button is on the top left, while the Y button is on the top right.

When you plug your PC controller into your Debian 12 system and run Nestopia, the emulator will assign the logical buttons A and B to the physical buttons A and B on your PC controller. However, this does not match the original layout of the NES controller. As a result, you will get a bugged input where the physical B button is mapped to A in the game, and vice versa.

Solution 1: Remap the NES Gamepad Input in Nestopia

To fix this problem, you need to remap the NES gamepad input in Nestopia so that it matches the original layout of the NES controller. To do this, follow these steps:

  1. Launch Nestopia from your applications menu or terminal.
  2. Go to Options > Input… from the menu bar.
  3. In the Input Settings window, select Player 1 from the Port drop-down menu.
  4. Click on Configure… next to Device.
  5. In the Configure Device window, click on each button under NES and press the corresponding button on your PC controller that you want to map it to. For example, click on A under NES and press X on your PC controller. This will map A in Nestopia to X on your PC controller, which matches the original layout of the NES controller.
  6. Repeat step 5 for all buttons under NES until you have remapped them all according to your preference.
  7. Click OK to save your changes and close the Configure Device window.
  8. Click OK again to close the Input Settings window.

Now you can play NES games in Nestopia with a fixed input that matches your physical buttons.

Solution 2: Create Custome Configuration File

The solution is to create a custom configuration file for Nestopia that overrides the default button mapping. This file should be named nestopia.cfg and placed in your home directory (~). The file should contain the following lines:

Controller1A = 0
Controller1B = 1

This tells Nestopia to map the physical B button (0) to the A button action, and the physical A button (1) to the B button action. You can also change other input settings in this file, such as turbo buttons, autofire, and analog sticks.

After creating this file, you need to restart Nestopia for the changes to take effect. You can also test your gamepad input by pressing F8 in Nestopia to open the input configuration menu. You should see that the buttons are mapped correctly now.

How to Avoid this Problem in the Future?

If you want to avoid this problem in the future, you can do one of two things:

  • Use a different emulator that has a correct default mapping for NES games. For example, you can try FCEUX, which is another popular NES/Famicom emulator for Linux that has a more accurate default mapping for PC controllers.
  • Use a different controller that has a similar layout to the NES controller. For example, you can use an official Nintendo NES gamepad that has a Wii connector, and an adapter for PC for that. This way, you can enjoy NES games with an authentic feel and no need for remapping.

Frequently Asked Questions

Here are some common questions and answers related to this topic:

Question: How do I know which version of Nestopia I have installed?

Answer: You can check which version of Nestopia you have installed by going to Help > About… from the menu bar. You will see a window that shows information about Nestopia, including its version number.

Question: How do I update Nestopia to get bug fixes and new features?

Answer: You can update Nestopia by using your distribution’s package manager or Software Center. Alternatively, you can download and install Nestopia from its official website or GitHub repository.

Question: How do I take screenshots of NES games in Nestopia?

Answer: You can take screenshots of NES games in Nestopia by pressing F12 on your keyboard while playing a game. The screenshot will be saved as a PNG file in your home directory under .nestopia/screenshots.

Question: How do I record videos of NES games in Nestopia?

Answer: You can record videos of NES games in Nestopia by using a third-party screen recording software, such as OBS Studio or SimpleScreenRecorder. You can then configure the software to capture the Nestopia window and save the video as a file.


We hope this article has helped you fix the bugged default NES gamepad input in Nestopia on Debian 12. If you have any questions or feedback, please leave a comment below. Happy retro gaming!


This article is intended for informational purposes only. We are not responsible for any damage or loss caused by following the instructions in this article. Using an emulator may be illegal in some countries or regions depending on the copyright laws and regulations. Always check your local laws before using an emulator and only use it with games that you own legally.

Alex Lim is a certified IT Technical Support Architect with over 15 years of experience in designing, implementing, and troubleshooting complex IT systems and networks. He has worked for leading IT companies, such as Microsoft, IBM, and Cisco, providing technical support and solutions to clients across various industries and sectors. Alex has a bachelor’s degree in computer science from the National University of Singapore and a master’s degree in information security from the Massachusetts Institute of Technology. He is also the author of several best-selling books on IT technical support, such as The IT Technical Support Handbook and Troubleshooting IT Systems and Networks. Alex lives in Bandar, Johore, Malaysia with his wife and two chilrdren. You can reach him at [email protected] or follow him on Website | Twitter | Facebook

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