Hardware GameCube Adapter: Z and R issue

[PinkJuri]

I bought a GC adapter for the Wii U so me and my friend could use our controllers in Sm4sh but the issue with the one I got is that it rerouted Z to R and made the actual Z button useless, any known fixes I could try to get it working again [Has a PC and Wii U mode btw] (And no I can't ship it back because I bought it in July and just now decided to ask about this).

 

[KevinLSX]

Is it mayflash

 

[PinkJuri]

Is it mayflash

I wish I had enough money to buy a mayflash, it's some off brand suppier and the box is red and white with no clear indication of who made it

 

[The Real Jdbye]

I wish I had enough money to buy a mayflash, it's some off brand suppier and the box is red and white with no clear indication of who made it

You get what you pay for. The Mayflash one was only $20 last I checked which really isn't a bad price and you know it'll work.
I doubt there's anything you can do to fix it. There must be something wrong with the firmware of the microcontroller which you can't do anything about.