diff --git a/usr.bin/mkimg/mkimg.h b/usr.bin/mkimg/mkimg.h
--- a/usr.bin/mkimg/mkimg.h
+++ b/usr.bin/mkimg/mkimg.h
@@ -29,6 +29,9 @@
 
 #include <sys/queue.h>
 #include <sys/types.h>
+#include <stdbool.h>
+
+extern bool reproducible;
 
 struct part {
 	TAILQ_ENTRY(part) link;
diff --git a/usr.bin/mkimg/mkimg.1 b/usr.bin/mkimg/mkimg.1
--- a/usr.bin/mkimg/mkimg.1
+++ b/usr.bin/mkimg/mkimg.1
@@ -41,6 +41,7 @@
 .Op Fl f Ar format
 .Op Fl o Ar outfile
 .Op Fl a Ar active
+.Op Fl R
 .Op Fl v
 .Op Fl y
 .Op Fl s Ar scheme Op Fl p Ar partition ...
@@ -138,6 +139,11 @@
 same time.
 .Pp
 The
+.Fl R
+option enables reproducible mode: any timestamps or random identifiers will
+be fixed so as to ensure consistent output.
+.Pp
+The
 .Fl v
 option increases the level of output that the
 .Nm
diff --git a/usr.bin/mkimg/mkimg.c b/usr.bin/mkimg/mkimg.c
--- a/usr.bin/mkimg/mkimg.c
+++ b/usr.bin/mkimg/mkimg.c
@@ -61,6 +61,8 @@
 static uint64_t min_capacity = 0;
 static uint64_t max_capacity = 0;
 
+bool reproducible = false;
+
 struct partlisthead partlist = TAILQ_HEAD_INITIALIZER(partlist);
 u_int nparts = 0;
 
@@ -561,7 +563,7 @@
 
 	bcfd = -1;
 	outfd = 1;	/* Write to stdout by default */
-	while ((c = getopt_long(argc, argv, "a:b:c:C:f:o:p:s:vyH:P:S:T:",
+	while ((c = getopt_long(argc, argv, "a:b:c:C:f:o:p:s:vyH:P:RS:T:",
 	    longopts, NULL)) != -1) {
 		switch (c) {
 		case 'a':	/* ACTIVE PARTITION, if supported */
@@ -606,6 +608,9 @@
 			if (error)
 				errc(EX_DATAERR, error, "partition");
 			break;
+		case 'R':
+			reproducible = true;
+			break;
 		case 's':	/* SCHEME */
 			if (scheme_selected() != NULL)
 				usage("multiple schemes given");
@@ -675,6 +680,9 @@
 	if (max_capacity != 0 && min_capacity > max_capacity)
 		usage("minimum capacity cannot be larger than the maximum one");
 
+	if (reproducible)
+		srandom(42);
+
 	if (secsz > blksz) {
 		if (blksz != 0)
 			errx(EX_DATAERR, "the physical block size cannot "
diff --git a/usr.bin/mkimg/uuid.c b/usr.bin/mkimg/uuid.c
--- a/usr.bin/mkimg/uuid.c
+++ b/usr.bin/mkimg/uuid.c
@@ -45,20 +45,9 @@
 }
 #endif	/* __APPLE__ */
 
-#ifdef __FreeBSD__
-#include <sys/uuid.h>
-
-static void
-osdep_uuidgen(mkimg_uuid_t *uuid)
-{
-
-	uuidgen((void *)uuid, 1);
-}
-#endif	/* __FreeBSD__ */
-
-#ifdef __linux__
+#if defined(__linux__) || defined(__FreeBSD__)
+#include <sys/time.h>
 #include <stdlib.h>
-#include <time.h>
 
 static void
 osdep_uuidgen(mkimg_uuid_t *uuid)
@@ -68,7 +57,9 @@
 	u_int i;
 	uint16_t seq;
 
-	if (gettimeofday(&tv, NULL) == -1)
+	if (reproducible)
+		memset(&tv, 0, sizeof(tv));
+	else if (gettimeofday(&tv, NULL) == -1)
 		abort();
 
 	time += (uint64_t)tv.tv_sec * 10000000LL;