Hi all. I had the same problem: Marvin connected fine to my previous iDevices, sending ebooks to my devices was a piece of cake, but on my new iPad Air 2 Marvin opens the Calibre connector and then all stops.
At first I had serious issues installing the IOS plug in (error message No module named PyQt4), after I installed the beta version of this plug in, then again the plug in via Calibre itself, I finally could configure the plug in (iPad via Marvin).
Still, Calibre does not "read" Marvin from my iPad, there are no buttons allowing me to link to my device.
And yes, I have updated all apps and programs to latest versions, and only 1 iDevice plugged in; running on Maverick - hesitant to go on Yosemite.
I am a (donating) fan of Calibre since it came on the market. My current work around to get books on my iPad are via Dropbox.
Hope help is on it's way. I have contacted the Marvin app designer, they refer me to Calibre...
