NES 2.0 Mapper 256 Submapper Proposal

Several VTxx-based plug-and-play consoles use a simple protection scheme intended to prevent interchanging the ROM data between different consoles. The protection scheme works by simply swapping the addresses of the bankswitch registers.

I have made a submapper proposal for mapper 256 to deal with this issue. Test ROM attached.

Since no objections have been raised after almost seven weeks, I am adding the proposal to the main submapper page.