I just bought a mint condition A7R on Ebay. Everything works fantastic.
The actual firmware is the 1.02. I downloaded the Update_ILCE7RV110 from the official Sony Us site.
I'm trying to do the update from a Mac with a fully charged Sony original battery and fallowing the exact steps as described.
When I get to connecting the camera to the computer it stays long on verifying connection, then it tells to turn off the camera, pull the battery and restart the update software.
The camera is on Mass storage USB mode.
It happens again and again. I tried in my macbook pro and is the same. Changed USB cable and is the same.
Curious is that I get connection to other software like Capture One with no problem.