Wait, you don't need to make a new iso to play it in usbloadergx. Just set the game load options to "Ocarina On" and run the game. Just set up your sd card like you were using usb gecko instead of a usbloader.
Well, My disk drive broke, that's why I use usblgx. I do use the Orcarina cheats in usblgx; that's how I get my modded iso to work. I've been told that any usbloaders don't register SD Card mods. Or am I wrong.