diff --git a/sbin/reboot/reboot.c b/sbin/reboot/reboot.c
--- a/sbin/reboot/reboot.c
+++ b/sbin/reboot/reboot.c
@@ -88,7 +88,7 @@
 }
 
 static void
-write_nextboot(const char *fn, const char *kernel, const char *env, bool force)
+write_nextboot(const char *fn, const char *env, bool force)
 {
 	FILE *fp;
 	struct statfs sfs;
@@ -112,12 +112,11 @@
 
 	fp = fopen(fn, "w");
 	if (fp == NULL)
-		E("Can't create %s to boot %s", fn, kernel);
+		E("Can't create %s", fn);
 
-	if (fprintf(fp,"%s%skernel=\"%s\"\n",
+	if (fprintf(fp,"%s%s",
 	    supported ? "nextboot_enable=\"YES\"\n" : "",
-	    env ? env : "",
-	    kernel) < 0) {
+	    env ? env : "") < 0) {
 		int e;
 
 		e = errno;
@@ -182,8 +181,8 @@
 	int ch, howto, i, sverrno;
 	bool Dflag, fflag, lflag, Nflag, nflag, qflag;
 	uint64_t pageins;
-	const char *user, *kernel = NULL;
-	char *env = NULL, *oldenv, *v;
+	const char *user;
+	char *kernel = NULL, *env = NULL, *oldenv, *v;
 
 
 	if (strstr(getprogname(), "halt") != NULL) {
@@ -291,9 +290,16 @@
 				errx(1, "%s is not a file", k);
 			free(k);
 		}
-		write_nextboot(PATH_NEXTBOOT, env, kernel, fflag);
+		oldenv = env;
+		v = quoted(kernel);
+		asprintf(&env, "%s%s=%s\n", oldenv ? oldenv : "", "kernel", v);
+		if (env == NULL)
+			errx(1, "No memory to build env array");
+		free(v);
+		free(oldenv);
 	}
 
+	write_nextboot(PATH_NEXTBOOT, env, fflag);
 	/* Log the reboot. */
 	if (!lflag)  {
 		if ((user = getlogin()) == NULL)