Thanks to the testing efforts of 4cc3ss we now have a verified D3100 version of the Time Restriction Removal patch.
The Web Firmware Patch Tool tool has been updated to v1.2 and supports patching Nikon D3100 & D5100 & D7000 firmware.
Interested in more, come join the us at Nikon Hacker, or use the Online Patch Tool (Help)