Sometimes you want to have your USB drive in the other port, either because your port stops working or you may need to have another device in the bottom port.
How do I change ports
Simply plugging the USB drive in the top port will work for most things however not for USB Loader GX and other emulators, however its just a matter of changing the port settings in USB Loader GX.
So from within USB Loader GX go to settings
Then from there select Hard drive settings
Once in hard drive settings, look for where it says USB port, it should read port 0 for the bottom port
We can change this setting to 0 (Bottom port), 1 (Top USB port) or Both, setting it to both is fine however it will make the opening of USB Loader GX slightly slower while it checks both ports, but for testing and other set ups Both will be fine.
You MUST exit USB Loader GX and restart your wii (unplugging is best) for the Wii to rescan the changed port settings.