Apps that work:
!!! Firefox (touches in the application are incorrect, you need to click below to get to the desired area)
Chrome (at the start request for choosing a search engine, the accept button goes beyond the screen, if you try for a long time you can get it and it will be accepted. There is also no square screen, which hides the browser menu.)
Yandex browser
Telegram
Google disk
Gmail
YouTube
Relive
Runkeeper
Hidden settings (allows you to use features hidden by the developer by removing links in the menu. So I found how to turn off power saving mode for certain applications)
there is a standard keyboard on the firmware out of the box, the only nuance is the enter button, it is very small and hard to hit. If you install Gboard from Google, then it is larger and goes beyond the display, it is not possible to use it.
Set and forget for lemfo z40. There is only the need to be able to write with a keyboard that covers the text screen, but it does not matter the bottom key can hide the keyboard to see the text.