diff --git a/cangen.c b/cangen.c
index 26d28c6..e26c08b 100644
--- a/cangen.c
+++ b/cangen.c
@@ -89,8 +89,10 @@ void print_usage(char *prg)
 	fprintf(stderr, "         -f            (generate CAN FD CAN frames)\n");
 	fprintf(stderr, "         -b            (generate CAN FD CAN frames"
 		" with bitrate switch (BRS))\n");
+	fprintf(stderr, "         -E            (generate CAN FD CAN frames"
+		" with error state (ESI))\n");
 	fprintf(stderr, "         -R            (send RTR frame)\n");
-	fprintf(stderr, "         -m            (mix -e -f -b -R frames)\n");
+	fprintf(stderr, "         -m            (mix -e -f -b -E -R frames)\n");
 	fprintf(stderr, "         -I <mode>     (CAN ID"
 		" generation mode - see below)\n");
 	fprintf(stderr, "         -L <mode>     (CAN data length code (dlc)"
@@ -145,6 +147,7 @@ int main(int argc, char **argv)
 	unsigned char extended = 0;
 	unsigned char canfd = 0;
 	unsigned char brs = 0;
+	unsigned char esi = 0;
 	unsigned char mix = 0;
 	unsigned char id_mode = MODE_RANDOM;
 	unsigned char data_mode = MODE_RANDOM;
@@ -181,7 +184,7 @@ int main(int argc, char **argv)
 	signal(SIGHUP, sigterm);
 	signal(SIGINT, sigterm);
 
-	while ((opt = getopt(argc, argv, "ig:ebfmI:L:D:xp:n:c:vRh?")) != -1) {
+	while ((opt = getopt(argc, argv, "ig:ebEfmI:L:D:xp:n:c:vRh?")) != -1) {
 		switch (opt) {
 
 		case 'i':
@@ -205,6 +208,11 @@ int main(int argc, char **argv)
 			canfd = 1;
 			break;
 
+		case 'E':
+			esi = 1; /* error state indicator implies CAN FD */
+			canfd = 1;
+			break;
+
 		case 'm':
 			mix = 1;
 			canfd = 1; /* to switch the socket into CAN FD mode */
@@ -379,6 +387,8 @@ int main(int argc, char **argv)
 			maxdlen = CANFD_MAX_DLEN;
 			if (brs)
 				frame.flags |= CANFD_BRS;
+			if (esi)
+				frame.flags |= CANFD_ESI;
 		} else {
 			mtu = CAN_MTU;
 			maxdlen = CAN_MAX_DLEN;
@@ -504,8 +514,10 @@ resend:
 			i = random();
 			extended = i&1;
 			canfd = i&2;
-			if (canfd)
+			if (canfd) {
 				brs = i&4;
+				esi = i&8;
+			}
 			rtr_frame = ((i&24) == 24); /* reduce RTR frames to 1/4 */
 		}
 	}