Here is an overview of what was done. The situation is more grim than rumored, but there is hope as well.
First of all, the fatalities are gone upon booting in any home console mode. None of the debug dips will enable them.
Second of all, there is a lockout that prevents you from booting in MVS mode. You will go to the red copyright screen, and the game will lock up. Anyone who thinks this is a hack job had better revise their opinion now... this was deliberate and it was done with the Debug BIOS in mind.
Can you play your cart in MVS mode? Sure. Just boot in home mode, start the game, and change to MVS mode on the fly. Think you beat the lockout? Nope. The lockout is not to prevent you from playing in MVS mode... the lockout is to prevent you from using the MVS Soft Dips to enable the level 3 / with violence setting. Basically, the lockout kicks in whenever the cart tries to read the MVS Soft Dips, not whenever the cart is played in MVS mode. You can go to the attract screen in Home mode, switch to MVS, insert a coin, and you are locked out again.
Here is what I conclude:
1. The MVS Soft Dips must be what the lockout is for, because you can use MVS mode fine.
2. The fatalities and full MVS version must be present on the cart, otherwise you wouldn't need the Soft Dips locked out.
3. SNKP either: a. put a violence code that must be used to enable the fatalities, or b. made completely sure that it was impossible to see the fatalities on the home system
It may be that only another BIOS can beat this, by allowing the user to access the Violence setting without triggering the Soft Dip lockout. However, if the Debug BIOS has any way to access this setting on the fly, that would work as well. The lockout is frustrating, but it is also the 1 ray of hope for everyone... it simply wouldn't be there if SNKP had gotten rid of the fatalities.