Hi,
I'm on a Macbook OS X 10.5.6 and I'm running the latest 1.31NA firmware. I installed the latest shareport utility for OS X by running SharePortUtility_10_4. The file Cosetup did nothing for me. I was able to plug in SandDisk USB Cruzer 2.0 GB stick. Was able to write an 87MB .mov file and was able to watch it. It transfered at a rate of 1.1MB/s (8.8 Mbps) which is quite slow. Now the moment I tried to seek a specific spot in the movie, Finder just gave me the rainbow circle and I couldn't even reboot.
The firmware 1.31NA in itself has been working fine for me, but the initial release of the SharePort utility for OS X is very buggy. Use it if you want to play around with, but I wouldn't trust it for data that is important. Anyone also having the same issue?