void btime_state::init_zoar()
{
	uint8_t *rom = memregion("maincpu")->base();

	/* At location 0xD50A is what looks like an undocumented opcode. I tried
	   implementing it given what opcode 0x23 should do, but it still didn't
	   work in demo mode. So this could be another protection or a bad ROM read.
	   I'm NOPing it out for now. */
	memset(&rom[0xd50a],0xea,8);

	m_audio_nmi_enable_type = AUDIO_ENABLE_AY8910;
}