I meet a problem when I try to connect to wifi on raspbian(2016-05-13-raspbian-jessie-mate-gpu-bpi-m3-sd-emmc.img)
I google it and it says that I should add current account(pi) to the group “netdev”, and then log in again. But the problem is not solved after these operations.
What should I do? are there anybody encountered the same problem?
You can try to install Wicd after the installation reboot your BPI and it should work fine 
If you need help with the installation you can ask me but there is a good instructions from the Ubuntusers-Wiki
Good luck 
greetings, root_Padi