Hacking Any idea what this little piece of hardware could be?

[ElConsolero]

 

[Pk11]

That looks like the adapter to use a Guitar Hero grip on an original DS

 

[zerofalcon]

As mentioned, it's the adapter (gba sized) for the guitar hero grip.

 

[City]

As previously mentioned, it's the adapter for the guitar hero grip that goes in the GBA slot of the Nintendo DS.

 

[ElConsolero]

Thanks guys!

I see now, its a replacement to fit into old Nintendo DS