tennapop

I am looking at purchasing an APPRADIO 2, since BestBuy and Crutchfield have them on sale right now. I did hava couple of quick questions on the new firmware and the iPhone 5. I have both a 5 and a 4s (one is personal, the other is a work phone). Am I able to add a USB splitter to the back of the deck and run both sets of cables so I can use either or, or will I only be able to use one or the other with the current firmware? Also, both of my devices are jailbroken. Does appradio extentions still work? Lastly, does the TR7 relay still work as well? TIA!!!