Index: head/sbin/savecore/savecore.c
===================================================================
--- head/sbin/savecore/savecore.c
+++ head/sbin/savecore/savecore.c
@@ -973,7 +973,45 @@
 	close(fddev);
 }
 
+/* Prepend "/dev/" to any arguments that don't already have it */
 static char **
+devify(int argc, char **argv)
+{
+	char **devs;
+	int i, l;
+
+	devs = malloc(argc * sizeof(*argv));
+	if (devs == NULL) {
+		logmsg(LOG_ERR, "malloc(): %m");
+		exit(1);
+	}
+	for (i = 0; i < argc; i++) {
+		if (strncmp(argv[i], _PATH_DEV, sizeof(_PATH_DEV) - 1) == 0)
+			devs[i] = strdup(argv[i]);
+		else {
+			char *fullpath;
+
+			fullpath = malloc(PATH_MAX);
+			if (fullpath == NULL) {
+				logmsg(LOG_ERR, "malloc(): %m");
+				exit(1);
+			}
+			l = snprintf(fullpath, PATH_MAX, "%s%s", _PATH_DEV,
+			    argv[i]);
+			if (l < 0) {
+				logmsg(LOG_ERR, "snprintf(): %m");
+				exit(1);
+			} else if (l >= PATH_MAX) {
+				logmsg(LOG_ERR, "device name too long");
+				exit(1);
+			}
+			devs[i] = fullpath;
+		}
+	}
+	return (devs);
+}
+
+static char **
 enum_dumpdevs(int *argcp)
 {
 	struct fstab *fsp;
@@ -1069,6 +1107,7 @@
 {
 	cap_rights_t rights;
 	const char *savedir;
+	char **devs;
 	int i, ch, error, savedirfd;
 
 	checkfor = compress = clear = force = keep = verbose = 0;
@@ -1132,7 +1171,9 @@
 		argv++;
 	}
 	if (argc == 0)
-		argv = enum_dumpdevs(&argc);
+		devs = enum_dumpdevs(&argc);
+	else
+		devs = devify(argc, argv);
 
 	savedirfd = open(savedir, O_RDONLY | O_DIRECTORY);
 	if (savedirfd < 0) {
@@ -1148,10 +1189,10 @@
 	}
 
 	/* Enter capability mode. */
-	init_caps(argc, argv);
+	init_caps(argc, devs);
 
 	for (i = 0; i < argc; i++)
-		DoFile(savedir, savedirfd, argv[i]);
+		DoFile(savedir, savedirfd, devs[i]);
 
 	/* Emit minimal output. */
 	if (nfound == 0) {
Index: head/share/man/man5/rc.conf.5
===================================================================
--- head/share/man/man5/rc.conf.5
+++ head/share/man/man5/rc.conf.5
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 23, 2020
+.Dd June 28, 2020
 .Dt RC.CONF 5
 .Os
 .Sh NAME
@@ -3469,7 +3469,9 @@
 .Pa /etc/fstab
 will be used as dump device.
 Otherwise, the value of this variable is passed as the argument to
-.Xr dumpon 8 .
+.Xr dumpon 8
+and
+.Xr savecore 8 .
 To disable crash dumps, set this variable to
 .Dq Li NO .
 .It Va dumpon_flags