Here are a few things to look out for if you are having trouble updating the firmware on the Tahoe board:

1. If you are updating from 2.x to 3.0, you must change the firmware keys.
This blog post has the steps you need to follow:
http://blog.devicesolutions.net/200...framework/

2. Check your USB setup. The Tahoe should be connected directly to the PC and not go through a hub. You should also make sure there are no add-on boards connected to the Tahoe during the update process.

3. Make sure you don't have any other applications open that could interfere with the USB. This includes MFDeploy and Visual Studio.

4. Make sure you have the correct firmware for your board - running Tahoe firmware on a Tahoe-II will result in a blank screen. Running the Tahoe-II update will fix this.

5. If you are still having problems, try putting the board into boot-loader mode (hold down up and down buttons, then press reset), and then run the update application.