Index: sys/kern/kern_shutdown.c
===================================================================
--- sys/kern/kern_shutdown.c	(revision 225515)
+++ sys/kern/kern_shutdown.c	(working copy)
@@ -706,7 +706,10 @@
 	if (length != 0 && (offset < di->mediaoffset ||
 	    offset - di->mediaoffset + length > di->mediasize)) {
 		printf("Attempt to write outside dump device boundaries.\n");
-		return (ENXIO);
+	printf("offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
+		    (intmax_t)offset, (intmax_t)di->mediaoffset,
+		    (uintmax_t)length, (intmax_t)di->mediasize);
+		return (ENOSPC);
 	}
 	return (di->dumper(di->priv, virtual, physical, offset, length));
 }