Upgrade my mini to 4415 recently. Initially was OK but when I shut it down and restart it "Error Unsupported Hardware" appear. Shut it down again and unplug my 1T external drive, restart it again and it's OK. Tried a few times and the same result happens. Seems for 4415, I need to unplug the USB everytime I want to swtich it on. Downgraded to 3852.

Hope to get a fix on this.