Thank you for contacting us. The problem is most likely due to the host end's driver versus our IC chip on MB559UEA-1S. Could you double check that your computer has the most up to date driver for the firewire? If you are using an onboard firewire port, please make sure to check the motherboard's firewire chipset firmware updates. If you using a firewire add on card, please check with the add on card's chipset firmware update on firewire, Updating to the newest driver may help you resolve the current issue.
Please let me know if you have any other questions. Thanks!