diff --git a/Makefile.common b/Makefile.common
index d1b6c78..506a5e7 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -44,6 +44,7 @@ SOURCES_C         += \
                   $(SOURCE_DIR)/cpu_cores/eighty/z80_ops.c \
                   $(SOURCE_DIR)/cpu_cores/eighty/z80_wrap.c
 else
+CFLAGS            += -DUSE_Z80
 SOURCES_C         += $(SOURCE_DIR)/cpu_cores/z80/z80.c
 endif
 
diff --git a/source/ports/libretro/libretro_state.c b/source/ports/libretro/libretro_state.c
index fa1bc94..ee2a165 100644
--- a/source/ports/libretro/libretro_state.c
+++ b/source/ports/libretro/libretro_state.c
@@ -69,7 +69,10 @@ void system_load_state_mem(void)
 
    /* Load Z80 context */
    state_read(Z80_Context, sizeof(z80_t));
+
+#ifdef USE_Z80
    Z80.irq_callback = sms_irq_callback;
+#endif
 
    /* Load YM2413 context */
    state_read(YM2413_GetContextPtr(), YM2413_GetContextSize());