diff --git a/src/mess/machine/md_slot.c b/src/mess/machine/md_slot.c
index bf72a8d0763..958bb6431a8 100644
--- a/src/mess/machine/md_slot.c
+++ b/src/mess/machine/md_slot.c
@@ -538,7 +538,7 @@ int base_md_cart_slot_device::load_nonlist()
 
 void base_md_cart_slot_device::call_unload()
 {
-	if (m_cart->get_nvram_size())
+	if (m_cart && m_cart->get_nvram_size())
 		battery_save(m_cart->get_nvram_base(), m_cart->get_nvram_size());
 }
 
diff --git a/src/mess/machine/nes_slot.c b/src/mess/machine/nes_slot.c
index 656071a969d..2c5af6762f6 100644
--- a/src/mess/machine/nes_slot.c
+++ b/src/mess/machine/nes_slot.c
@@ -1,6 +1,6 @@
 #include "emu.h"
-#include "machine/nes_slot.h"
 #include "hashfile.h"
+#include "machine/nes_slot.h"
 
 #define NES_BATTERY_SIZE 0x2000
 
@@ -1112,9 +1112,9 @@ bool nes_cart_slot_device::call_load()
 
 void nes_cart_slot_device::call_unload()
 {
-	if (m_cart->get_battery_size())
+	if (m_cart && m_cart->get_battery_size())
 		battery_save(m_cart->get_battery_base(), m_cart->get_battery_size());
-	if (m_cart->get_mapper_bram_size())
+	if (m_cart && m_cart->get_mapper_bram_size())
 		battery_save(m_cart->get_mapper_bram_base(), m_cart->get_mapper_bram_size());
 }