diff --git a/drivers/power/reset/nvmem-reboot-mode.c b/drivers/power/reset/nvmem-reboot-mode.c
index 41530b70cfc4..d260715fccf6 100644
--- a/drivers/power/reset/nvmem-reboot-mode.c
+++ b/drivers/power/reset/nvmem-reboot-mode.c
@@ -10,6 +10,7 @@
 #include <linux/nvmem-consumer.h>
 #include <linux/platform_device.h>
 #include <linux/reboot-mode.h>
+#include <linux/slab.h>
 
 struct nvmem_reboot_mode {
 	struct reboot_mode_driver reboot;
@@ -19,12 +20,22 @@ struct nvmem_reboot_mode {
 static int nvmem_reboot_mode_write(struct reboot_mode_driver *reboot,
 				    unsigned int magic)
 {
-	int ret;
 	struct nvmem_reboot_mode *nvmem_rbm;
+	size_t buf_len;
+	void *buf;
+	int ret;
 
 	nvmem_rbm = container_of(reboot, struct nvmem_reboot_mode, reboot);
 
-	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, sizeof(magic));
+	buf = nvmem_cell_read(nvmem_rbm->cell, &buf_len);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+	kfree(buf);
+
+	if (buf_len > sizeof(magic))
+		return -EINVAL;
+
+	ret = nvmem_cell_write(nvmem_rbm->cell, &magic, buf_len);
 	if (ret < 0)
 		dev_err(reboot->dev, "update reboot mode bits failed\n");