How to update the firmware in TellStick and TellStick Duo using Mac OS X
Open the terminal. Run the following command:
sudo launchctl unload /Library/LaunchDaemons/com.telldus.service.plist
You need to enter your password.
Now you can run the flasher utility, which can be downloaded here:
http://download.telldus.com/TellStick/Software/TellStickNetFlasher/TellStickNetFlasher.dmg (yes, despite its name it works for TellStick and TellStick Duo too)