diff --git a/src/devices/machine/i8255.cpp b/src/devices/machine/i8255.cpp
index 0ae0a9d24ac..8f91652875f 100644
--- a/src/devices/machine/i8255.cpp
+++ b/src/devices/machine/i8255.cpp
@@ -299,6 +299,10 @@ void i8255_device::device_start()
 	save_item(NAME(m_inte1));
 	save_item(NAME(m_inte2));
 	save_item(NAME(m_intr));
+	
+	m_force_portb_in = false;
+	m_force_portc_out = false;
+	m_dont_clear_output_latches = false;
 }
 
 
@@ -651,8 +655,18 @@ void i8255_device::set_mode(uint8_t data)
 {
 	m_control = data;
 
+	if(m_force_portb_in)
+		m_control = m_control | CONTROL_PORT_B_INPUT;
+
+	if(m_force_portc_out)
+	{
+		m_control = m_control & ~CONTROL_PORT_C_UPPER_INPUT;
+		m_control = m_control & ~CONTROL_PORT_C_LOWER_INPUT;
+	}
+	
 	// group A
-	m_output[PORT_A] = 0;
+	if(!m_dont_clear_output_latches)
+		m_output[PORT_A] = 0;
 	m_input[PORT_A] = 0;
 	m_ibf[PORT_A] = 0;
 	m_obf[PORT_A] = 1;
@@ -678,7 +692,8 @@ void i8255_device::set_mode(uint8_t data)
 	LOG("I8255 Port C Lower Mode: %s\n", (port_c_lower_mode() == MODE_OUTPUT) ? "output" : "input");
 
 	// group B
-	m_output[PORT_B] = 0;
+	if(!m_dont_clear_output_latches)
+		m_output[PORT_B] = 0;
 	m_input[PORT_B] = 0;
 	m_ibf[PORT_B] = 0;
 	m_obf[PORT_B] = 1;
@@ -694,7 +709,8 @@ void i8255_device::set_mode(uint8_t data)
 		m_out_pb_cb((offs_t)0, m_tri_pb_cb(0));
 	}
 
-	m_output[PORT_C] = 0;
+	if(!m_dont_clear_output_latches)
+		m_output[PORT_C] = 0;
 	m_input[PORT_C] = 0;
 
 	output_pc();
@@ -1000,3 +1016,20 @@ WRITE_LINE_MEMBER( i8255_device::pc6_w )
 		}
 	}
 }
+
+
+// AMS40489 (Amstrad Plus/GX4000 ASIC PPI implementation)
+ams40489_ppi_device::ams40489_ppi_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+	: i8255_device(mconfig,tag,owner,clock)
+{}
+
+void ams40489_ppi_device::device_reset() { i8255_device::device_reset(); }
+
+void ams40489_ppi_device::device_start()
+{
+	i8255_device::device_start();
+	
+	m_force_portb_in = true;
+	m_force_portc_out = true;
+	m_dont_clear_output_latches = true;
+}
diff --git a/src/devices/machine/i8255.h b/src/devices/machine/i8255.h
index 3d7e1e0daa7..407a1cbef4e 100644
--- a/src/devices/machine/i8255.h
+++ b/src/devices/machine/i8255.h
@@ -111,6 +111,10 @@ protected:
 	virtual void device_start() override;
 	virtual void device_reset() override;
 
+	bool m_force_portb_in;
+	bool m_force_portc_out;
+	bool m_dont_clear_output_latches;
+	
 private:
 	inline void check_interrupt(int port);
 	inline void set_ibf(int port, int state);
@@ -158,9 +162,23 @@ private:
 	int m_intr[2];              // interrupt
 };
 
+// AMS40489 ASIC (Amstrad Plus/GX4000 PPI implementation)
+class ams40489_ppi_device : public i8255_device
+{
+public:
+	// construction/destruction
+	ams40489_ppi_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+protected:
+	// device-level overrides
+	virtual void device_start() override;
+	virtual void device_reset() override;
+	
+};
 
 // device type definition
 DECLARE_DEVICE_TYPE(I8255, i8255_device)
 DECLARE_DEVICE_TYPE(I8255A, i8255_device)
+DECLARE_DEVICE_TYPE(AMS40489_PPI, ams40489_ppi_device)
 
 #endif // MAME_MACHINE_I8255_H
diff --git a/src/mame/drivers/amstrad.cpp b/src/mame/drivers/amstrad.cpp
index 84bf75be645..8a04c5d358b 100644
--- a/src/mame/drivers/amstrad.cpp
+++ b/src/mame/drivers/amstrad.cpp
@@ -1047,7 +1047,7 @@ MACHINE_CONFIG_START(amstrad_state::cpcplus)
 	MCFG_MACHINE_START_OVERRIDE(amstrad_state, plus )
 	MCFG_MACHINE_RESET_OVERRIDE(amstrad_state, plus )
 
-	MCFG_DEVICE_ADD("ppi8255", I8255, 0)
+	MCFG_DEVICE_ADD("ppi8255", AMS40489_PPI, 0)
 	MCFG_I8255_IN_PORTA_CB(READ8(*this, amstrad_state, amstrad_ppi_porta_r))
 	MCFG_I8255_OUT_PORTA_CB(WRITE8(*this, amstrad_state, amstrad_ppi_porta_w))
 	MCFG_I8255_IN_PORTB_CB(READ8(*this, amstrad_state, amstrad_ppi_portb_r))
@@ -1091,6 +1091,7 @@ MACHINE_CONFIG_START(amstrad_state::cpcplus)
 	MCFG_CASSETTE_FORMATS(cdt_cassette_formats)
 	MCFG_CASSETTE_DEFAULT_STATE(CASSETTE_STOPPED | CASSETTE_MOTOR_DISABLED | CASSETTE_SPEAKER_ENABLED)
 	MCFG_CASSETTE_INTERFACE("cpc_cass")
+	MCFG_SOFTWARE_LIST_ADD("cass_list","cpc_cass")
 
 	MCFG_UPD765A_ADD("upd765", true, true)
 
@@ -1098,6 +1099,7 @@ MACHINE_CONFIG_START(amstrad_state::cpcplus)
 
 	MCFG_FLOPPY_DRIVE_ADD("upd765:0", amstrad_floppies, "3ssdd", floppy_image_device::default_floppy_formats)
 	MCFG_FLOPPY_DRIVE_ADD("upd765:1", amstrad_floppies, "35ssdd", floppy_image_device::default_floppy_formats)
+	MCFG_SOFTWARE_LIST_ADD("flop_list","cpc_flop")
 
 	MCFG_DEVICE_ADD("exp", CPC_EXPANSION_SLOT, 0)
 	MCFG_DEVICE_SLOT_INTERFACE(cpcplus_exp_cards, nullptr, false)
@@ -1125,7 +1127,7 @@ MACHINE_CONFIG_START(amstrad_state::gx4000)
 	MCFG_MACHINE_START_OVERRIDE(amstrad_state, gx4000 )
 	MCFG_MACHINE_RESET_OVERRIDE(amstrad_state, gx4000 )
 
-	MCFG_DEVICE_ADD("ppi8255", I8255, 0)
+	MCFG_DEVICE_ADD("ppi8255", AMS40489_PPI, 0)
 	MCFG_I8255_IN_PORTA_CB(READ8(*this, amstrad_state, amstrad_ppi_porta_r))
 	MCFG_I8255_OUT_PORTA_CB(WRITE8(*this, amstrad_state, amstrad_ppi_porta_w))
 	MCFG_I8255_IN_PORTB_CB(READ8(*this, amstrad_state, amstrad_ppi_portb_r))