diff --git a/target/linux/bcm27xx/base-files/lib/upgrade/platform.sh b/target/linux/bcm27xx/base-files/lib/upgrade/platform.sh
index 37c77edb34..a48b7cc08a 100644
--- a/target/linux/bcm27xx/base-files/lib/upgrade/platform.sh
+++ b/target/linux/bcm27xx/base-files/lib/upgrade/platform.sh
@@ -94,6 +94,6 @@ platform_copy_config() {
 		cp -af "$UPGRADE_BACKUP" "/boot/$BACKUP_FILE"
 		tar -C / -zxvf "$UPGRADE_BACKUP" boot/cmdline.txt boot/config.txt
 		sync
-		unmount /boot
+		umount /boot
 	fi
 }