I managed to get myself in a two-factor authentication pickle. My Apple id is associated with a Mac (currently running OS X Yosemite), an iPhone and an iPad.
The iPad just came back from repair and I needed to restore it from the cloud. Unfortunately before doing that I lost my iPhone! I now have nothing that can receive the two-factor authentication codes. (Didn't see that one coming!)
My Mac is tied to my iCloud account and Apple Id, and I see that Sierra can receive these codes and that I can upgrade from Yosemite which is what's currently running on the Macbook Pro.
If I upgrade to Sierra will that mean my Mac can then also receive the two factor codes (allowing me then to get my iPad back up and running)?
Or will I be out of luck as I may need to use two-factor to get the laptop properly set up with Sierra? If that's the case then I do not want to upgrade as it means I may lose the limited iCloud access that I have via the Mac.
N.B. Yes, have a full trustworthy backup of the Mac on Time Machine.