I strongly recommend getting a lan adapter for your wii u if you have a free ethernet (could even be fastethernet) port and cable in your switch or router or keystone or whatever youre using, its twice as fast and no weird shenanigans with the horrible network card :3
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I recommend just going with the official nintendo one, because I bought two diffirent ones with the same chipset as the wii lan adapter (ax88772a)(it should work(but it didnt)) and they just didnt work so i gave up and bought an official one for like 20 bucks