WORST case scenario, if you dumped your nand, and turned it back on with the stick in the machine, it would write the same nand it already had on to the box again. That's assuming you are dumping your nand as updflash.bin. and it's starting from Xell. Otherwise, yes, spaz2203 is quite accurate indeed. You would have 1) A Dumped nand, and 2) An xbox that has been turned back on.
I seem to have a similar problem to many others with the new update. Games seem to time out, or lag, significantly more since the new update. Granted, it's also since the new TU4 of Black Ops II.... But there is a marked system link performance difference between the older version, and the new version. All related Dashlaunch settings as stated on Original Post have been adjusted.