I've had a leap motion for a while now, and recently a project surged for which the Leap would be perfect.

Had not played with it for a bit, so when I opened the controller it asked to upgrade the firmware. After that the Leap motion stopped to respond.

I was a V.06.05 board version.

This is what I had to do to fix it:

Download the firmware reset tool from this link

mkdir /tmp/lm
cp -r /Volumes/LM_FirmwareReset_Mac/ /tmp/lm
cd /tmp/lm
chmod 775 FirmwareReset
./FirmwareReset

Then just follow the instructions:

Leap Motion Firmware Reset tool
===============================

           ____________________________________________________
          |                                                    |
          |  Please select "Pause Tracking" in the Leap        |
          |  Motion Tray Icon.                                 |
          |                                                    |
          |              Press Enter to continue.              |
          |____________________________________________________|


Please plug in your Leap Motion Controller.


The entire process should take less than a couple of minutes.

Restoring firmware (Part 1/2)
   ... Done
Restoring firmware (Part 2/2)
   ... Done
Firmware update succeeded. Press Enter to quit.

After quitting, you must unplug and replug your Leap Motion Controller.
Then, select "Resume Tracking" in the Leap Motion tray icon.

Happy leaping!