CAUTION: below method is danger. please do not.
New method without hacking was found, just dial the *#*#33284#*#*.
Steps to enable USB debugging in Nokia 8110 4G (2018)
- Mount SD card on your PC using USB.
(If you are a Mac user, please use Android File Transfer)
- Download smith.zip and copy to root directory of sdcard.
- Power off Nokia 8110 4G.
- Keep pressing up button and press power button, then device will show Recovery Menu.
- Select “Apply update from SD card” (Press power button to Enter).
- Select smith.zip to rewrite settings file.
- Back to Menu, and select “Wipe data/factory reset”.
- Select “Reboot system now” to reboot.
- After setting up, you will find “Developer” in Settings/Device.
- Enter to “Developer/Debugger”, and select “ADB and DevTools” to enable USB debugging.