Is this on version 1.4.0.?
I had a similar situation with and AIO HP 6010xi. HP advised some serious HP program removal involving pref. folder and play list etc. Maybe you could check with HP for some definitive answers.
Good luck.
I think you might be overengineering.
This may be oversimplfying but if the firewire cable is bad or the firewire port you would display the same symptons.
Also, we have had a lot of units in for repair that have had the ports shorted due to ESD's (Electro static discharge)
Hope this helps.