diff --git a/src/nvr_at.c b/src/nvr_at.c
index 91ee4a949..9a98968d2 100644
--- a/src/nvr_at.c
+++ b/src/nvr_at.c
@@ -981,9 +981,9 @@ nvr_at_init(const device_t *info)
     memset(local->lock, 0x00, nvr->size);
     local->def   = 0xff /*0x00*/;
     local->flags = 0x00;
-    switch (info->local & 7) {
+    switch (info->local & 0x0f) {
         case 0: /* standard AT, no century register */
-            if (info->local == 16) {
+            if (info->local == 32) {
                 local->flags |= FLAG_P6RP4_HACK;
                 nvr->irq    = 8;
                 local->cent = RTC_CENTURY_AT;
@@ -996,13 +996,13 @@ nvr_at_init(const device_t *info)
         case 1: /* standard AT */
         case 5: /* AMI WinBIOS 1994 */
         case 6: /* AMI BIOS 1995 */
-            if (info->local == 9)
+            if ((info->local & 0x0f) == 1)
                 local->flags |= FLAG_PIIX4;
             else {
                 local->def = 0x00;
-                if ((info->local & 7) == 5)
+                if ((info->local & 0x0f) == 5)
                     local->flags |= FLAG_AMI_1994_HACK;
-                else if ((info->local & 7) == 6)
+                else if ((info->local & 0x0f) == 6)
                     local->flags |= FLAG_AMI_1995_HACK;
                 else
                     local->def = 0xff;
@@ -1015,7 +1015,7 @@ nvr_at_init(const device_t *info)
             nvr->irq    = 8;
             local->cent = RTC_CENTURY_PS;
             local->def  = 0x00;
-            if (info->local & 8)
+            if (info->local & 0x10)
                 local->flags |= FLAG_NO_NMI;
             break;
 
@@ -1023,15 +1023,15 @@ nvr_at_init(const device_t *info)
             nvr->irq    = 1;
             local->cent = RTC_CENTURY_AT;
             local->def  = 0xff;
-            if (info->local & 8)
+            if (info->local & 0x10)
                 local->flags |= FLAG_NO_NMI;
             break;
 
         case 4: /* IBM AT */
-            if (info->local == 12) {
+            if (info->local & 0x10) {
                 local->def = 0x00;
                 local->flags |= FLAG_AMI_1992_HACK;
-            } else if (info->local == 20)
+            } else if (info->local == 36)
                 local->def = 0x00;
             else
                 local->def = 0xff;
@@ -1069,7 +1069,7 @@ nvr_at_init(const device_t *info)
         /* Set up the I/O handler for this device. */
         io_sethandler(0x0070, 2,
                       nvr_read, NULL, NULL, nvr_write, NULL, NULL, nvr);
-        if (info->local & 8) {
+        if (info->local & 0x10) {
             io_sethandler(0x0072, 2,
                           nvr_read, NULL, NULL, nvr_write, NULL, NULL, nvr);
         }
@@ -1180,7 +1180,7 @@ const device_t piix4_nvr_device = {
     .name          = "Intel PIIX4 PC/AT NVRAM",
     .internal_name = "piix4_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 9,
+    .local         = 0x10 | 1,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1220,7 +1220,7 @@ const device_t ami_1992_nvr_device = {
     .name          = "AMI Color 1992 PC/AT NVRAM",
     .internal_name = "ami_1992_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 12,
+    .local         = 0x10 | 4,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1234,7 +1234,7 @@ const device_t ami_1994_nvr_device = {
     .name          = "AMI WinBIOS 1994 PC/AT NVRAM",
     .internal_name = "ami_1994_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 13,
+    .local         = 0x10 | 5,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1248,7 +1248,7 @@ const device_t ami_1995_nvr_device = {
     .name          = "AMI WinBIOS 1995 PC/AT NVRAM",
     .internal_name = "ami_1995_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 14,
+    .local         = 0x10 | 6,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1262,7 +1262,7 @@ const device_t via_nvr_device = {
     .name          = "VIA PC/AT NVRAM",
     .internal_name = "via_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 15,
+    .local         = 0x10 | 7,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1276,7 +1276,7 @@ const device_t p6rp4_nvr_device = {
     .name          = "ASUS P/I-P6RP4 PC/AT NVRAM",
     .internal_name = "p6rp4_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 16,
+    .local         = 32,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,
@@ -1290,7 +1290,7 @@ const device_t amstrad_megapc_nvr_device = {
     .name          = "Amstrad MegapC NVRAM",
     .internal_name = "amstrad_megapc_nvr",
     .flags         = DEVICE_ISA | DEVICE_AT,
-    .local         = 20,
+    .local         = 36,
     .init          = nvr_at_init,
     .close         = nvr_at_close,
     .reset         = nvr_at_reset,