diff --git a/source/ftl/map.c b/source/ftl/map.c
index b7e25ef..61e16e6 100644
--- a/source/ftl/map.c
+++ b/source/ftl/map.c
@@ -132,7 +132,7 @@ int write_upage(struct ftl_map *map, const void *page,
 		return -1;
 
 	if (page && flash_write(map->dev, map->head << map->log2_page_size, page,
-		map->log2_page_size) == 0)
+		1 << map->log2_page_size) == 0)
 		return -1;
 
 	return write_page_desc(map, page_desc);