Hello, I have a nexus 7 16 mb, so first generation like you Yaytech. I also have an Irig microphone a bit desperate tomake it work!!!
Tell mw whether it works with you now on yours because I see you have both models! And what is square reader?
"*edit*
IT WORKS! I just looked up Square in the app store, and it shows up (it's hidden to the original N7, because it's not compatible). Installed, plugged in the reader, punched in $1.00 (min charge), and swiped my card to test. It works! (I was then able to cancel the payment, so if anyone else wants to try this, go for it, free test.)
Tablets: 2nd gen Nexus 7 32gb, 1st gen Nexus 7 16gb
Phone: Droid MAXX
Retired: OG Droid, Droid RAZR (RIP), Galaxy Nexus (backup phone)"
Igor