The old device (iPhone 4) cannot login with my apple ID and requests for me to enter a verification code after I give my password. BUT when I allow for the old device to use the apple ID from a trusted device, the old device does not display anything to enter the provided code!... any idea?
iPhone 4, iOS 7.1.2
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.
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.
IT worked like a charm. Thanks a lot.
How to add an iOS 7.1.2 device with two-step verification code?
