I also tried to update xbox dashboard and failed at the first step I guess , although I have done dashlaunch updates in the past without a problem ( from 2.32 to 3.04 )
I copied dashlaunch 3.08 and started the default.xex , prompted me to update , hit ok , then said "patches not current, would you like to update" hit yes , then reboot , ok . It shut down and then when I tried to start it again the only thing that powers on is the green dot in the middle and the controller stays in "searching state"(all 4 lights blink) . I think I followed the steps in your video tutorial and still, something went wrong for me .I am waiting for an anwser if you have encountered this problem before. Thanks !