diff --git a/sbin/geom/class/part/geom_part.c b/sbin/geom/class/part/geom_part.c
index 94e44bef39b3..58dbc3c1c07a 100644
--- a/sbin/geom/class/part/geom_part.c
+++ b/sbin/geom/class/part/geom_part.c
@@ -56,6 +56,10 @@ uint32_t PUBSYM(version) = 0;
 static char optional[] = "";
 static char flags[] = "C";
 
+static char bootcode_param[] = "bootcode";
+static char index_param[] = "index";
+static char partcode_param[] = "partcode";
+
 static void gpart_bootcode(struct gctl_req *, unsigned int);
 static void gpart_show(struct gctl_req *, unsigned int);
 
@@ -64,14 +68,16 @@ struct g_command PUBSYM(class_commands)[] = {
 		{ 'b', "start", NULL, G_TYPE_STRING },
 		{ 's', "size", NULL, G_TYPE_STRING },
 		{ 't', "type", NULL, G_TYPE_STRING },
-		{ 'i', "index", optional, G_TYPE_STRING },
+		{ 'i', index_param, optional, G_TYPE_STRING },
 		{ 'l', "label", optional, G_TYPE_STRING },
 		{ 'f', "flags", flags, G_TYPE_STRING },
 		G_OPT_SENTINEL },
 	  "geom", NULL
 	},
 	{ "bootcode", 0, gpart_bootcode, {
-		{ 'b', "bootcode", NULL, G_TYPE_STRING },
+		{ 'b', bootcode_param, optional, G_TYPE_STRING },
+		{ 'p', partcode_param, optional, G_TYPE_STRING },
+		{ 'i', index_param, optional, G_TYPE_STRING },
 		{ 'f', "flags", flags, G_TYPE_STRING },
 		G_OPT_SENTINEL },
 	  "geom", NULL
@@ -85,7 +91,7 @@ struct g_command PUBSYM(class_commands)[] = {
 	  "provider", NULL
 	},
 	{ "delete", 0, NULL, {
-		{ 'i', "index", NULL, G_TYPE_STRING },
+		{ 'i', index_param, NULL, G_TYPE_STRING },
 		{ 'f', "flags", flags, G_TYPE_STRING },
 		G_OPT_SENTINEL },
 	  "geom", NULL
@@ -95,7 +101,7 @@ struct g_command PUBSYM(class_commands)[] = {
 		G_OPT_SENTINEL },
 	  "geom", NULL },
 	{ "modify", 0, NULL, {
-		{ 'i', "index", NULL, G_TYPE_STRING },
+		{ 'i', index_param, NULL, G_TYPE_STRING },
 		{ 'l', "label", optional, G_TYPE_STRING },
 		{ 't', "type", optional, G_TYPE_STRING },
 		{ 'f', "flags", flags, G_TYPE_STRING },
@@ -286,38 +292,150 @@ gpart_show(struct gctl_req *req, unsigned int fl __unused)
 	geom_deletetree(&mesh);
 }
 
-static void
-gpart_bootcode(struct gctl_req *req, unsigned int fl __unused)
+static void *
+gpart_bootfile_read(const char *bootfile, ssize_t *size)
 {
 	struct stat sb;
-	const char *bootfile;
 	void *code;
-	int error, fd, size;
+	int fd;
 
-	bootfile = gctl_get_ascii(req, "bootcode");
-	if (bootfile == NULL)
-		errx(EXIT_FAILURE, "Missing bootfile argument");
-
-	error = stat(bootfile, &sb);
-	if (error)
-		errx(EXIT_FAILURE, "%s: not found", bootfile);
+	if (stat(bootfile, &sb) == -1)
+		err(EXIT_FAILURE, "%s", bootfile);
 	if (!S_ISREG(sb.st_mode))
 		errx(EXIT_FAILURE, "%s: not a regular file", bootfile);
-	if (sb.st_size >= 1024*1024)
-		errx(EXIT_FAILURE, "%s: file too big", bootfile);
+	if (sb.st_size == 0)
+		errx(EXIT_FAILURE, "%s: empty file", bootfile);
+	if (*size > 0 && sb.st_size >= *size)
+		errx(EXIT_FAILURE, "%s: file too big (%zu limit)", bootfile,
+		    *size);
 
-	size = sb.st_size;
+	*size = sb.st_size;
 
 	fd = open(bootfile, O_RDONLY);
 	if (fd == -1)
-		errx(EXIT_FAILURE, "%s: unable to open", bootfile);
-	code = malloc(size);
+		err(EXIT_FAILURE, "%s", bootfile);
+	code = malloc(*size);
 	if (code == NULL)
-		errx(EXIT_FAILURE, "out of memory");
-	if (read(fd, code, size) != size)
-		errx(EXIT_FAILURE, "%s: unable to read", bootfile);
+		err(EXIT_FAILURE, NULL);
+	if (read(fd, code, *size) != *size)
+		err(EXIT_FAILURE, "%s", bootfile);
 	close(fd);
 
-	gctl_change_param(req, "bootcode", size, code);
-	gctl_issue(req);
+	return (code);
+}
+
+static void
+gpart_write_partcode(struct gctl_req *req, int idx, void *code, ssize_t size)
+{
+	char dsf[128];
+	struct gmesh mesh;
+	struct gclass *classp;
+	struct ggeom *gp;
+	struct gprovider *pp;
+	const char *s;
+	int error, fd;
+
+	s = gctl_get_ascii(req, "class");
+	if (s == NULL)
+		abort();
+	error = geom_gettree(&mesh);
+	if (error != 0)
+		errc(EXIT_FAILURE, error, "Cannot get GEOM tree");
+	classp = find_class(&mesh, s);
+	if (classp == NULL) {
+		geom_deletetree(&mesh);
+		errx(EXIT_FAILURE, "Class %s not found.", s);
+	}
+	s = gctl_get_ascii(req, "geom");
+	gp = find_geom(classp, s);
+	if (gp == NULL)
+		errx(EXIT_FAILURE, "No such geom: %s.", s);
+
+	LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
+		s = find_provcfg(pp, "index");
+		if (s == NULL)
+			continue;
+		if (atoi(s) == idx)
+			break;
+	}
+
+	if (pp != NULL) {
+		snprintf(dsf, sizeof(dsf), "/dev/%s", pp->lg_name);
+		fd = open(dsf, O_WRONLY);
+		if (fd == -1)
+			err(EXIT_FAILURE, "%s", dsf);
+		if (lseek(fd, size, SEEK_SET) != size)
+			errx(EXIT_FAILURE, "%s: not enough space", dsf);
+		if (lseek(fd, 0, SEEK_SET) != 0)
+			err(EXIT_FAILURE, "%s", dsf);
+		if (write(fd, code, size) != size)
+			err(EXIT_FAILURE, "%s", dsf);
+		close(fd);
+	} else
+		errx(EXIT_FAILURE, "invalid partition index");
+
+	geom_deletetree(&mesh);
+}
+
+static void
+gpart_bootcode(struct gctl_req *req, unsigned int fl __unused)
+{
+	const char *s;
+	char *sp;
+	void *bootcode, *partcode;
+	size_t bootsize, partsize;
+	int error, idx;
+
+	if (gctl_has_param(req, bootcode_param)) {
+		s = gctl_get_ascii(req, bootcode_param);
+		bootsize = 64 * 1024;		/* Arbitrary limit. */
+		bootcode = gpart_bootfile_read(s, &bootsize);
+		error = gctl_change_param(req, bootcode_param, bootsize,
+		    bootcode);
+		if (error)
+			errc(EXIT_FAILURE, error, "internal error");
+	} else {
+		bootcode = NULL;
+		bootsize = 0;
+	}
+
+	if (gctl_has_param(req, partcode_param)) {
+		s = gctl_get_ascii(req, partcode_param);
+		partsize = bootsize * 1024;
+		partcode = gpart_bootfile_read(s, &partsize);
+		error = gctl_delete_param(req, partcode_param);
+		if (error)
+			errc(EXIT_FAILURE, error, "internal error");
+	} else {
+		partcode = NULL;
+		partsize = 0;
+	}
+
+	if (gctl_has_param(req, index_param)) {
+		if (partcode == NULL)
+			errx(EXIT_FAILURE, "-i is only valid with -p");
+		s = gctl_get_ascii(req, index_param);
+		idx = strtol(s, &sp, 10);
+		if (idx < 1 || *s == '\0' || *sp != '\0')
+			errx(EXIT_FAILURE, "invalid partition index");
+		error = gctl_delete_param(req, index_param);
+		if (error)
+			errc(EXIT_FAILURE, error, "internal error");
+	} else
+		idx = 0;
+
+	if (partcode != NULL) {
+		if (idx == 0)
+			errx(EXIT_FAILURE, "missing -i option");
+		gpart_write_partcode(req, idx, partcode, partsize);
+	} else {
+		if (bootcode == NULL)
+			errx(EXIT_FAILURE, "no -b nor -p");
+	}
+
+	if (bootcode != NULL) {
+		s = gctl_issue(req);
+		if (s != NULL)
+			errx(EXIT_FAILURE, "%s", s);
+	}
 }