Backport several changes from M&K

src/machine/m_amstrad.c

@@ -2348,7 +2348,16 @@ machine_amstrad_init(const machine_t *model, int type)
     memset(ams, 0x00, sizeof(amstrad_t));
     ams->type = type;
 
-    device_add(&amstrad_nvr_device);
+    switch(type) {
+	case AMS_PC200:
+	case AMS_PPC512:
+		device_add(&amstrad_no_nmi_nvr_device);
+		break;
+
+	default:
+		device_add(&amstrad_nvr_device);
+		break;
+    }
 
     machine_common_init(model);
 

src/machine/m_ps2_mca.c

@@ -1348,7 +1348,7 @@ machine_ps2_common_init(const machine_t *model)
 
         dma16_init();
         ps2_dma_init();
-	device_add(&ps_nvr_device);
+        device_add(&ps_no_nmi_nvr_device);
         pic2_init();
 
         pit_ps2_init();