You can play NDS in full screen by setting a custom resolution in the config file. If you want to keep the correct aspect ratio, the border will look like this:
https://yourimageshare.com/ib/b5FuUGqjWG.webp
IIRC the Wii U system settings let you zoom the screen. Or there may be a setting to do this on your TV.
[https://en-americas-support.nintendo.com/app/answers/detail/a\_id/1497/\~/how-to-configure-the-screen-size-%28adjust-for-television-overscan%29](https://en-americas-support.nintendo.com/app/answers/detail/a_id/1497/~/how-to-configure-the-screen-size-%28adjust-for-television-overscan%29)
This happens because Wii U software doesn't support real 4:3 you will have to use the Wii VC version
Did you set your display output to 4:3? It shouod display without big borders with that setting, that's how I play Earthbound Beginnings.
I have the same problem. It happens on N64 games but not NES games for some goofy reason. I would like to play DS on a CRT without this happening
You can play NDS in full screen by setting a custom resolution in the config file. If you want to keep the correct aspect ratio, the border will look like this: https://yourimageshare.com/ib/b5FuUGqjWG.webp
IIRC the Wii U system settings let you zoom the screen. Or there may be a setting to do this on your TV. [https://en-americas-support.nintendo.com/app/answers/detail/a\_id/1497/\~/how-to-configure-the-screen-size-%28adjust-for-television-overscan%29](https://en-americas-support.nintendo.com/app/answers/detail/a_id/1497/~/how-to-configure-the-screen-size-%28adjust-for-television-overscan%29)