diff --git a/src/mess/drivers/cybiko.c b/src/mess/drivers/cybiko.c
index 71c1895c6c7..8ba6231c714 100644
--- a/src/mess/drivers/cybiko.c
+++ b/src/mess/drivers/cybiko.c
@@ -94,21 +94,59 @@ static ADDRESS_MAP_START( cybikoxt_mem, AS_PROGRAM, 16, cybiko_state )
 	AM_RANGE( 0xe00000, 0xefffff ) AM_READ( cybikoxt_key_r )
 ADDRESS_MAP_END
 
+READ16_MEMBER(cybiko_state::serflash_r)
+{
+	if (m_flash1->so_r())
+	{
+		return 0x08;
+	}
+
+	return 0;
+}
+
+READ16_MEMBER(cybiko_state::clock_r)
+{
+	if (m_rtc->sda_r())
+	{
+		return (0x01|0x04);
+	}
+
+	return 0x04;
+}
+
+READ16_MEMBER(cybiko_state::xtclock_r)
+{
+	if (m_rtc->sda_r())
+	{
+		return 0x40;
+	}
+
+	return 0;
+}
+
+READ16_MEMBER(cybiko_state::xtpower_r)
+{
+	// bit 7 = on/off button
+	// bit 6 = battery charged if "1"
+	return 0xc0c0;
+}
+
 //////////////////////
 // ADDRESS MAP - IO //
 //////////////////////
 
 static ADDRESS_MAP_START( cybikov1_io, AS_IO, 16, cybiko_state )
-	AM_RANGE( 0xfffe40, 0xffffff ) AM_READWRITE( cybikov1_io_reg_r, cybikov1_io_reg_w )
+	AM_RANGE(h8_device::PORT_3, h8_device::PORT_3) AM_READ(serflash_r)
 ADDRESS_MAP_END
 
 static ADDRESS_MAP_START( cybikov2_io, AS_IO, 16, cybiko_state )
-	AM_RANGE( 0xfffe40, 0xffffff ) AM_READWRITE( cybikov2_io_reg_r, cybikov2_io_reg_w )
+	AM_RANGE(h8_device::PORT_3, h8_device::PORT_3) AM_READ(serflash_r)
 ADDRESS_MAP_END
 
 static ADDRESS_MAP_START( cybikoxt_io, AS_IO, 16, cybiko_state )
-	AM_RANGE( 0xfffe40, 0xffffff ) AM_READWRITE( cybikoxt_io_reg_r, cybikoxt_io_reg_w )
-ADDRESS_MAP_END
+	AM_RANGE(h8_device::PORT_A, h8_device::PORT_A) AM_READ(xtpower_r)
+	AM_RANGE(h8_device::PORT_F, h8_device::PORT_F) AM_READ(xtclock_r)
+ADDRESS_MAP_END 								 
 
 /////////////////
 // INPUT PORTS //
@@ -340,10 +378,6 @@ static MACHINE_CONFIG_DERIVED( cybikoxt, cybikov1)
 	MCFG_CPU_PROGRAM_MAP(cybikoxt_mem )
 	MCFG_CPU_IO_MAP(cybikoxt_io )
 
-	// setup loopback
-	MCFG_DEVICE_MODIFY("maincpu:sci1")
-	MCFG_H8_SCI_TX_CALLBACK(DEVWRITELINE("sci1", h8_sci_device, rx_w));
-
 	// machine
 	MCFG_DEVICE_REMOVE("flash1")
 	MCFG_SST_39VF400A_ADD("flashxt")	
diff --git a/src/mess/includes/cybiko.h b/src/mess/includes/cybiko.h
index 5468633ee96..4d05639a281 100644
--- a/src/mess/includes/cybiko.h
+++ b/src/mess/includes/cybiko.h
@@ -58,6 +58,11 @@ public:
 	m_nvram(*this, "nvram")
 	{ }
 
+	DECLARE_READ16_MEMBER(serflash_r);
+	DECLARE_READ16_MEMBER(clock_r);
+	DECLARE_READ16_MEMBER(xtclock_r);
+	DECLARE_READ16_MEMBER(xtpower_r);
+
 	CYBIKO_RS232 m_rs232;
 	DECLARE_READ16_MEMBER(cybiko_lcd_r);
 	DECLARE_WRITE16_MEMBER(cybiko_lcd_w);
@@ -65,12 +70,6 @@ public:
 	DECLARE_READ16_MEMBER(cybikov2_key_r);
 	DECLARE_READ16_MEMBER(cybikoxt_key_r);
 	DECLARE_WRITE16_MEMBER(cybiko_usb_w);
-	DECLARE_READ16_MEMBER(cybikov1_io_reg_r);
-	DECLARE_READ16_MEMBER(cybikov2_io_reg_r);
-	DECLARE_READ16_MEMBER(cybikoxt_io_reg_r);
-	DECLARE_WRITE16_MEMBER(cybikov1_io_reg_w);
-	DECLARE_WRITE16_MEMBER(cybikov2_io_reg_w);
-	DECLARE_WRITE16_MEMBER(cybikoxt_io_reg_w);
 	int cybiko_key_r( offs_t offset, int mem_mask);
 	void cybiko_rs232_write_byte(int data);
 	void cybiko_rs232_pin_sck(int data);
diff --git a/src/mess/machine/cybiko.c b/src/mess/machine/cybiko.c
index 577a64124c0..58a18f26e22 100644
--- a/src/mess/machine/cybiko.c
+++ b/src/mess/machine/cybiko.c
@@ -65,7 +65,15 @@ void cybiko_state::machine_start()
 	cybiko_rs232_init();
 	// other
 	machine().add_notifier(MACHINE_NOTIFY_EXIT, machine_notify_delegate(FUNC(cybiko_state::machine_stop_cybiko),this));
-	m_nvram->set_base(m_ram->pointer(), RAMDISK_SIZE);
+
+	int nvram_size = RAMDISK_SIZE;
+
+	if (m_ram->size() < nvram_size)
+	{
+		nvram_size = m_ram->size();
+	}
+
+	m_nvram->set_base(m_ram->pointer(), nvram_size);
 }
 
 ///////////////////
@@ -213,6 +221,7 @@ READ16_MEMBER( cybiko_state::cybikoxt_key_r )
 	return cybiko_key_r(offset, mem_mask);
 }
 
+#if 0
 READ16_MEMBER( cybiko_state::cybikov1_io_reg_r )
 {
 	UINT16 data = 0;
@@ -469,6 +478,7 @@ WRITE16_MEMBER( cybiko_state::cybikoxt_io_reg_w )
 	}
 #endif
 }
+#endif
 
 // Cybiko Xtreme writes following byte pairs to 0x200003/0x200000
 // 00/01, 00/C0, 0F/32, 0D/03, 0B/03, 09/50, 07/D6, 05/00, 04/00, 20/00, 23/08, 27/01, 2F/08, 2C/02, 2B/08, 28/01