To enable the developer mode under a Nokia N9 mobile phone:
- From the Home screen > Tap on Settings > Security > Developper mode.
- A menu will be displayed, you can either choose between:
- Move the slider button next to "Developer mode" to the right to enable this option.
- You shall get a small warning messages, click on "Accept" to validate.
- Your phone will restart and the developer mode will be enabled.