I know the bottom usb port on the back of the HU is for connecting to a android phone, can the top port (iphone port) be used with a usb stick?

Yeah, the top port is used for file transfers/map updates. 

Think of the top USB as the ‘main’ one 

Thanks

On my 4200nex it's iPhone for USB1 and Android for USB2. I only use the ports with the USB connector that came with the radio. I haven't tried it any other way.

My 8200 came with one usb extension cable and one aux extension cable. I couldn't use the aux cable cuz the maestro rr requires you to plug their 3.5 mm jack into the aux port on back of hu.  I bought a extension cable from best buy and it seems to be working.