EFEM is the Engineering Menu known from the other older Motorola phones. In future that article will be updated with more information about it's features. At the moment we are providing you a tutorial regarding how to enable EFEM in your ROKR E2:
1. Establish telnet connection and do:
# cp /ezx_user/download/appwrite/am/UserMenuTree /mmc/mmca1/UserMenuTree.txt
2. Disconnect the phone and connect it in memory card mode. Open UserMenuTree.txt from your SD card with simple text editor and go to the end of the second line add the following string:
"4c99e984-bbc1-455f-981e-e5e06dec6872;"
without the quotes
3. Save the file and disconnect your phone. Again establish telnet connection and execute the following commands
# rm /ezx_user/download/appwrite/am/UserMenuTree
# cp /mmc/mmca1/UserMenuTree.txt /ezx_user/download/appwrite/am/UserMenuTree
4. Reboot your phone and enjoy FEM

Useful trick for expirienced users: Using VIM for Motorola ROKR E2 you will be able to edit the file directly in the file system

Thanks to WhiteMoto for the information on how to enable that