I also have a CSMKII and a deneb, and after changing the startup-delay of my usb stick I have no more problems.
Try to change the startup-delay setting in trident prefs. I've set the startup-delay of my usb-stick to 500, because I had similiar problems.
If you change the setting, don't forget to reflash the deneb flashrom, or else there will be an old version of psdstackloader in the flashrom.
