diff --git a/source/ftl/ftl.c b/source/ftl/ftl.c
index 27e23e9..68fdca4 100644
--- a/source/ftl/ftl.c
+++ b/source/ftl/ftl.c
@@ -650,9 +650,11 @@ int ftl_trim(struct ftl_journal *j, uint32_t va)
 
 	if (i == 32) {
 		j->root = UINT32_MAX;
-		/* TODO: how do we clean the FTL? */
 
-		return 0;
+		memset(&page_desc, 0xff, sizeof page_desc);
+		page_desc.nused_pages = 0;
+
+		return ftl_write_upage(j, NULL, &page_desc);
 	}
 
 	if (read_page_desc(j, &alt_page_desc, alt_va) < 0)