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In genesis_io_r add these two lines at 1217 & 1239:
				if(iport1 & 0x10 || iport2 & 0x20)
					return_value+=1;
full code:
 READ16_HANDLER ( genesis_io_r )
{
	/* 8-bit only, data is mirrored in both halves */

	UINT8 return_value = 0;

	switch (offset)
	{
		case 0:
		/* Charles MacDonald ( http://cgfm2.emuviews.com/ )
		    D7 : Console is 1= Export (USA, Europe, etc.) 0= Domestic (Japan)
		    D6 : Video type is 1= PAL, 0= NTSC
		    D5 : Sega CD unit is 1= not present, 0= connected.
		    D4 : Unused (always returns zero)
		    D3 : Bit 3 of version number
		    D2 : Bit 2 of version number
		    D1 : Bit 1 of version number
		    D0 : Bit 0 of version number
		*/
			return_value = 0x80; /* ? megatech is usa? */
			break;

		case 1: /* port A data (joypad 1) */

			if (genesis_io_ram[offset] & 0x40)
			{
				int iport = readinputport(9);
				return_value = iport & 0x3f;
			}
			else
			{
				int iport1 = readinputport(12);
				int iport2 = readinputport(7) >> 1;
				return_value = (iport1 & 0x10) + (iport2 & 0x20);
				if(iport1 & 0x10 || iport2 & 0x20)
					return_value+=1;
			}

			return_value = (genesis_io_ram[offset] & 0x80) | return_value;
			logerror ("reading joypad 1 , type %02x %02x\n",genesis_io_ram[offset] & 0x80, return_value &0x7f);
			if(bios_ctrl_inputs & 0x04) return_value = 0xff;
			break;

		case 2: /* port B data (joypad 1) */

			if (genesis_io_ram[offset] & 0x40)
			{
				int iport1 = (readinputport(9) & 0xc0) >> 6;
				int iport2 = (readinputport(8) & 0x0f) << 2;
				return_value = (iport1 + iport2) & 0x3f;
			}
			else
			{
				int iport1 = readinputport(12) << 2;
				int iport2 = readinputport(7) >> 2;
				return_value = (iport1 & 0x10) + (iport2 & 0x20);
				if(iport1 & 0x10 || iport2 & 0x20)
					return_value+=1;
			}
			return_value = (genesis_io_ram[offset] & 0x80) | return_value;
			logerror ("reading joypad 2 , type %02x %02x\n",genesis_io_ram[offset] & 0x80, return_value &0x7f);
			if(bios_ctrl_inputs & 0x04) return_value = 0xff;
			break;

		default:
			return_value = 0xe0;

	}
	return return_value | return_value << 8;



}