diff --git a/drivers/mtd/devices/sst25l.c b/drivers/mtd/devices/sst25l.c
index ac7d52b..c2baf33 100644
--- a/drivers/mtd/devices/sst25l.c
+++ b/drivers/mtd/devices/sst25l.c
@@ -180,8 +180,10 @@
 	mutex_lock(&flash->lock);
 
 	err = sst25l_wait_till_ready(flash);
-	if (err)
+	if (err) {
+		mutex_unlock(&flash->lock);
 		return err;
+	}
 
 	while (addr < end) {
 		err = sst25l_erase_sector(flash, addr);