Nokia 8110

https://www.nokia.com/en_int/phones/nokia-8110-4g

developer mode

*#*#33284#*#*
*#*#0574#*#*

https://community.phones.nokia.com/discussion/4840/i-want-to-enter-developer-mode

=> https://groups.google.com/forum/m/#!topic/bananahackers/oibDSjczSPI