I am trying to add an old iphone 4 back onto my account but although i can login to the device i dont believe two factor authentication works on IOS 7- my other devices give me a passcode but I am not prompted on the Iphone 4. I can't switch my Icloud account back from two factor authentication to two step verification. Whats the workaround?
iPhone 4 (8GB)
See the following from Two-factor authentication for Apple ID - Apple Support
If you use two-factor authentication with devices running older OS
versions—like an Apple TV (2nd or 3rd generation)—you might be asked to
add your six-digit verification code to the end of your password when
signing in. Get your verification code
from a trusted device running iOS 9 and later or OS X El Capitan and
later, or have it sent to your trusted phone number. Then type your
password followed by the six-digit verification code directly into the
password field.
Two Step Verification vs two factor authentication
