Phone is locked with an impossible to enter password

Question

As it appeared, the on-screen keyboard for entering the unlock password is missing English layout, although it for sure was present when the password has been created. Now the situation appears really bad:

• the phone (TP-LINK Neffos C9A, Android 8.1 NFUI 8.0) is locked,
• the password is not possible to enter because of missing keyboard layout,
• option for adding keyboard languages is not available,
• there is no option "Forgotten password" and
• Android Device Manager responds "Can't reach device" with either WiFi or 3G connection.

How to unlock the phone in such situation?

Answer 1

In case there is a problem with the on-screen keyboard most devices support to use an USB keyboard connected via USB On-The-Go (OTG) adapter to the phone - if the phone supports USB OTG at all.

The simpler an USB keyboard is the more likely it will work - keyboards with integrated USB hub and/or readers for smartcard or sd-card often cause problems and may not work.

Note that the USB keyboard works like a regular keyboard (not like the on-screen keyboard): key combinations like have be pressed at the same time, not one after another.

Answer 2

For people seeking for other answers, there is a flashable Zip file which deletes any lock screens. However you'd need a device with a custom recovery such as TWRP. Just flash the Zip and your lock screen will be gone on next restart.