diff --git a/src/mess/drivers/p8k.c b/src/mess/drivers/p8k.c
index 01161e2fa1e..95010fe438e 100644
--- a/src/mess/drivers/p8k.c
+++ b/src/mess/drivers/p8k.c
@@ -367,8 +367,11 @@ void p8k_state::fdc_drq(bool state)
 void p8k_state::machine_start()
 {
 	i8272a_device *fdc = machine().device<i8272a_device>("i8272");
-	fdc->setup_intrq_cb(i8272a_device::line_cb(FUNC(p8k_state::fdc_irq), this));
-	fdc->setup_drq_cb(i8272a_device::line_cb(FUNC(p8k_state::fdc_drq), this));
+	if (fdc)
+	{
+		fdc->setup_intrq_cb(i8272a_device::line_cb(FUNC(p8k_state::fdc_irq), this));
+		fdc->setup_drq_cb(i8272a_device::line_cb(FUNC(p8k_state::fdc_drq), this));
+	}
 }
 
 static const floppy_format_type p8k_floppy_formats[] = {
diff --git a/src/mess/includes/compis.h b/src/mess/includes/compis.h
index bccce8e821a..c74c8f4a29a 100644
--- a/src/mess/includes/compis.h
+++ b/src/mess/includes/compis.h
@@ -139,7 +139,7 @@ public:
 	m_centronics(*this, "centronics"),
 	m_uart(*this, "uart"),
 	m_rtc(*this, "mm58274c"),
-	m_fdc(*this, "upd765"),
+	m_fdc(*this, "i8272a"),
 	m_crtc(*this, "upd7220"),
 	m_video_ram(*this, "video_ram") { }
 
@@ -152,7 +152,7 @@ public:
 	required_device<centronics_device> m_centronics;
 	required_device<i8251_device> m_uart;
 	required_device<device_t> m_rtc;
-	required_device<upd765a_device> m_fdc;
+	required_device<i8272a_device> m_fdc;
 	required_device<upd7220_device> m_crtc;
 	DECLARE_READ16_MEMBER(compis_usart_r);
 	DECLARE_WRITE16_MEMBER(compis_usart_w);
diff --git a/src/mess/includes/sg1000.h b/src/mess/includes/sg1000.h
index 96553b4f1f6..bd34fd18982 100644
--- a/src/mess/includes/sg1000.h
+++ b/src/mess/includes/sg1000.h
@@ -101,12 +101,12 @@ public:
 		: sc3000_state(mconfig, type, tag),
 		  m_fdc(*this, UPD765_TAG),
 		  m_centronics(*this, CENTRONICS_TAG),
-		  m_floppy0(*this, FLOPPY_0)
+		  m_floppy0(*this, UPD765_TAG ":0:525hd")
 	{ }
 
 	required_device<upd765a_device> m_fdc;
 	required_device<centronics_device> m_centronics;
-	required_device<device_t> m_floppy0;
+	required_device<floppy_image_device> m_floppy0;
 
 	virtual void machine_start();
 	virtual void machine_reset();
diff --git a/src/mess/machine/compis.c b/src/mess/machine/compis.c
index eee3503983d..086e86befe2 100644
--- a/src/mess/machine/compis.c
+++ b/src/mess/machine/compis.c
@@ -159,7 +159,7 @@ static void compis_keyb_init(compis_state *state)
 /*-------------------------------------------------------------------------*/
 static void compis_fdc_reset(running_machine &machine)
 {
-	machine.device("upd765")->reset();
+	machine.device("i8272a")->reset();
 }
 
 void compis_state::compis_fdc_tc(int state)