Jim,
Maybe I can shed some light here. Apple does not allow the iPhone, iPad or iPod to be used as a USB drive, without connecting thru iTune. Android and Windows phones will allows this. We have several Android users that download the zip file to their phone and then plug the phone into the iFly 700, the iFly would then recognize the phone as a USB and then update as usual.
I have tried numerous USB apps for the iPhone with no success, they are all wireless USB or iTunes dependent. You might be able to get an adapter for the iPhone or iPad that would allow you to use a USB, however I do not think you can transfer a file from the iPad or iPhone going out to another device. I believe it is only for accessing files on the USB. Apple holds a lot of constraint on their devices and ties much of its data through iTunes. I hope this helps.