Ok, so if you’re using Google Authenticator to protect logins on servers or just for your own Google mail / apps login you may come across the situation where you want it on more than one device. For example I’ve an Android phone and a tablet, and sometimes the phone is like really far…. like across the desk… or in the kitchen… but I want to log in on my PC.
Problem comes when you set up an account on your device and activate it Google will stop accepting codes generated by the other instance.
A bit of a search (cheers Google) turns up a way around this which is probably stupidly obvious to anyone except me.
Set up your devices AT THE SAME TIME. Scan the barcode on one, then the other, THEN enter the validation code!
Simple when you think sideways!
Or just set the account up on the second device using the code rather than scanning the QR code.