If you are using windows to write the contents to the zip drive you are going to have that issue. Windows writes some hidden files into anything you insert, these files will change the calculated hash during validation thus giving you the error you get. NEVER insert the diagnostic key into a windows or mac machine, it will mess it up. If you put the flash drive into a linux machine, you can just erase the non-igt directory and you should be good to go. Also booting the machine with the ekey and the OS install flash drive will wipe the drive clean and just install OS, then you can install the game packages as you see fit.