Sonnet engineering has fixed this issue with some Fusion storage systems. This issue was addressed and fixed as follows:
APRIL, 2008: in Fusion D400Q and Fusion D500P systems with serial numbers beginning with J.
MAY 20, 2008: In Fusion D800RAID with serial numbers beginning with G.
All versions of Fusion R400Q and R800RAID are compatible with Seagate ES.2 Drives.
Note: Seagate ES.2 drives have lower performance than Sonnet recommended drives.
The Fusion D400Q and R400Q must have a hard drive in drive bay 1 when connected via USB, FireWire, or FireWire 800. This requirement is due to the Oxford bridge chip that controls USB and FireWire connectons. Drive bay 1 is the top bay in the Fusion D400Q and the left bay in the Fusion R400Q. As long as there is a drive in drive bay 1, bays 2-4 are unconstrained.
Note: This requirement does not apply to a direct SATA connection, which has no drive bay population requirements.