HARMONi Firmware Updater enables the FireWire port on iMac computers that have undergone HARMONi upgrade.
One important thing to note is that this firmware update has specific requirements. Your iMac model must be either 233 MHz, 266 MHz, or 333 MHz with Rev. A-D. If you meet these requirements, you can try out this update and hopefully get your FireWire port working as it should be.
Version 1.1: N/A