Hi there, i had the exact same problem. As soon as i tried the far right, nearest to the front of the pc port it detected no problem whatsoever, im fairly certain this is the most likely reason. (IMG:
style_emoticons/default/smile.gif) I take it your using bad flash method, if so then use textbooks guide, just plug the sata into the via port on the far right, then power on the pc and xbox with the sata loose out of the xbox. At dos plug it in and run idump, it will list the drive xtreme hopefully. Now turn the xbox off and hit the xtreme drive, it will fail, then wait 10 secs and turn the xbox back on and it should automatically start dumping .Repeat this using method using iflash. Good luck.