r8040 /src/mess/drivers/x1.c: [X1]: Added experimental cartslot support

For amusement I've did this, basically you can convert tape games into cartridge ones. Steps are:

1) Load a tape game under debug build;
2) add a bp at ff7d
3) now comes the neat part: open the memory viewer (CTRL+M), modify value [0x00] to 0x01, modify the header [0x01-0x0e] into whatever you want (presumably the name of the game in ASCII wink ), check HL register and modify value [0xff16-0xff17] accordingly (notice that z80 takes values in inverted order, for example: if HL = 0x1234, you should put 0x12 to [0xff17] and 0x34 to [0xff16]), and, optionally, remove the stack RAM clutter inside the rest of the work RAM (basically, 0xff00-0xffff memories).
4) finally, go into the debugger main window and write the following command:
save <name_of_the_rom>.rom,0,10000

With this basic tutorial, I've successfully converted Bokosuka Wars and Kagirinaki Tatakai. Presumably any tape with physical size bigger than 64k won't work without some dasm mods ... translated, any tape game that loads after the POST.