http://forums.windowscentral.com/samsung-ativ-s/353229-[guide]-how-update-8-1-2-a.html
The info is out there... However, since it costs $19 USD to get a Developer Account and Developer Unlock your handset, most won't care to. I would not pay $19 to change a carrier splash page... I went through the process of getting the Hack installed to help pankaj981 test his
debrand method on Lumia 830 RM-983. It did not work unfortunately, but I thought
that was worth a $19 gamble...
Changing the splash screen is explained inside the tool. It's just a toy I played with since I had already paid the entry fee.