The problem isn't the controller. The driver for the VIA 1394 Firewire controller in my computer loads just fine. However, when I connect the Buffalo drive, the drive doesn't appear in My Computer or Device Manager for several minutes, although it spins up and Win7 reports "SBP2 Compilant IEEE 1394 device". Finally, the drive appears in Device Manager as "BUFFALO INC. HDD IEEE 1394 SBP2 device" with an exclamation point in a yellow triangle icon next to it. When I go into the Volumes tab in the device properties, nothing will populate with the error "Volume information for this disk cannot be found."
I've also tried this in a Win 7 computer that has an Texas Instruments 1394 controller with the exact same result.
I, like you, didn't expect any trouble from a simple mass storage device after upgrading, but here we are. On top of that, I've been completely blown off by Buffalo as it looks like they never have even looked into it. This will be my last Buffalo storage purchase.