I don't think Game Genie had any uses for the Zelda titles. I just remember I could do loads of crap in the Super Mario Bros. games with it. I don't think it had any Zelda uses, or at least, I don't recall using it for Zelda, myself.
*Raises hand.*
The first Legend of Zelda relased in my lifetime was the original "Legend of Zelda." I actually remember when the NES was a shiny new thing. I was about 7 years old at the time, but didn't actually get my NES or LoZ until I was around 10.
I grew up on the Legend of Zelda...