An old thread, but still an issue with modern Android - I think I have the solution, I've just done it on three phones running android 7 and 9.
Remove the sim card.
Boot the phone and select none.
Turn off the phone and re-insert the sim.
Boot the phone and no screen lock.
If you add a lock you'll have to repeat the process to remove it - you can't remove it with the sim in.
Remove the sim card.
Boot the phone and select none.
Turn off the phone and re-insert the sim.
Boot the phone and no screen lock.
If you add a lock you'll have to repeat the process to remove it - you can't remove it with the sim in.
Facebook
Twitter
Instagram