diff --git a/VAX/vax630_sysdev.c b/VAX/vax630_sysdev.c
index ea58716d..0ab7e792 100644
--- a/VAX/vax630_sysdev.c
+++ b/VAX/vax630_sysdev.c
@@ -542,10 +542,23 @@ return SCPE_OK;
 
 /* NVR attach */
 
+/* Valid NVRAM contents are required for the Boot ROM to respect the
+   watch chip's CSRD VRT bit.  This empty NVRAM image avoids inconsistent
+   ROM behavior the first time the NVR device is attached (to an empty 
+   file).  Attaching a already existing file will overwrite this initial
+   contents with whatever the NVRAM file contains.  */
+uint8 nvr_empty_valid[NVRSIZE] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 
+    0x00, 0x00, 0x00, 0xFE, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFE, 
+    0xFF, 0x00, 0x00, 0xFE, 0xFF, 0x00, 0x48, 0x45, 0x41, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+    };
+
 t_stat nvr_attach (UNIT *uptr, char *cptr)
 {
 t_stat r;
 
+memcpy (nvr, nvr_empty_valid, NVRSIZE);
 uptr->flags = uptr->flags | (UNIT_ATTABLE | UNIT_BUFABLE);
 r = attach_unit (uptr, cptr);
 if (r != SCPE_OK)