diff --git a/sbin/reboot/reboot.8 b/sbin/reboot/reboot.8
--- a/sbin/reboot/reboot.8
+++ b/sbin/reboot/reboot.8
@@ -39,18 +39,22 @@
 .Op Fl DflNnpq
 .Op Fl e Ar variable=value
 .Op Fl k Ar kernel
+.Op Fl o Ar options
 .Nm
 .Op Fl cDdflNnpqr
 .Op Fl e Ar variable=value
 .Op Fl k Ar kernel
+.Op Fl o Ar options
 .Nm fasthalt
 .Op Fl DflNnpq
 .Op Fl e Ar variable=value
 .Op Fl k Ar kernel
+.Op Fl o Ar options
 .Nm fastboot
 .Op Fl dDflNnpq
 .Op Fl e Ar variable=value
 .Op Fl k Ar kernel
+.Op Fl o Ar options
 .Sh DESCRIPTION
 The
 .Nm halt
@@ -131,6 +135,9 @@
 .It Fl n
 The file system cache is not flushed.
 This option should probably not be used.
+.It Fl o Ar options
+This option
+allows the passing of kernel flags for the next boot.
 .It Fl p
 The system will turn off the power if it can.
 If the power down action fails, the system
diff --git a/sbin/reboot/reboot.c b/sbin/reboot/reboot.c
--- a/sbin/reboot/reboot.c
+++ b/sbin/reboot/reboot.c
@@ -191,7 +191,7 @@
 	} else
 		howto = 0;
 	Dflag = fflag = lflag = Nflag = nflag = qflag = false;
-	while ((ch = getopt(argc, argv, "cDdek:lNnpqr")) != -1)
+	while ((ch = getopt(argc, argv, "cDdek:lNnopqr")) != -1)
 		switch(ch) {
 		case 'c':
 			howto |= RB_POWERCYCLE;
@@ -230,6 +230,15 @@
 			nflag = true;
 			Nflag = true;
 			break;
+		case 'o':
+			oldenv = env;
+			v = quoted(kernel);
+			asprintf(&env, "%s%s=%s\n", oldenv ? oldenv : "", "kernel_options", v);
+			if (env == NULL)
+				errx(1, "No memory to build env array");
+			free(v);
+			free(oldenv);
+			break;
 		case 'p':
 			howto |= RB_POWEROFF;
 			break;