[minimaul]

Depends.

If it was stolen from the original owner then you don't really own the device legally and this is the anti-theft part of activation lock functioning as designed. If you're an innocent third party to the original theft, your remedy is to get a full refund.

If it was just because the original owner forgot to disable activation lock, you should be chasing them to unlock it for you. If they refuse, your remedy is to get a full refund.

edit: reputable recycling places require you to have disabled activation lock on functional devices, or they don't pay out.

[xapata]

I've got a bizarre situation in which an OS upgrade bricked my Mac. I can't remember the details now, but it was something about an interface change in which I had managed to activate 2FA, but the login interface didn't have an input box for it.

The device was old enough that I just heaved a sigh and gave it to Apple for recycling.

[minimaul]

There's actually a solution for that: https://support.apple.com/en-gb/HT204915

> What if I use two-factor authentication on a device running older software?

> If you use two-factor authentication with devices running older OS versions – such as an Apple TV (2nd or 3rd generation) – you may 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.

[Nexxxeh]

This weirdly works in some other places. Iirc one of the Amazon's seller login pages accepts the 2FA code appended to the password to avoid having to go through another page.