As we understand, The Firmware limits the use of other than WD drives, Let alone using 3.5" external HDD, You are welcome to try it, Most likely will fail as the FW will fail to spin the drive.
The only series that is known to work on the WD TV LIVE HUB is the WD 2.5" scorpio Blue series
http://www.wdc.com/en/products/products.aspx?id=140
Having said, You may want to experiment with WD drives, you may have better luck
Let us know
Cheers!
