diff --git a/source/fs/mufs/block.c b/source/fs/mufs/block.c
index 969ca6f..ca6f90b 100644
--- a/source/fs/mufs/block.c
+++ b/source/fs/mufs/block.c
@@ -32,6 +32,9 @@ int mufs_mark_block(struct mufs *fs, uint32_t block, int status)
 		sizeof data) == 0)
 		return -1;
 
+	if (flash_sync(fs->dev) < 0)
+		return -1;
+
 	return 0;
 }
 
diff --git a/source/fs/mufs/tree.c b/source/fs/mufs/tree.c
index 4d4a3e7..381b0fe 100644
--- a/source/fs/mufs/tree.c
+++ b/source/fs/mufs/tree.c
@@ -61,6 +61,9 @@ static int mufs_do_lookup(struct mufs *fs, uint32_t *page,
 		if (flash_write(dev, (base << dev->log2_block_size) +
 			index * sizeof entry, &entry, sizeof entry) == 0)
 			return -1;
+
+		if (flash_sync(dev) < 0)
+			return -1;
 	}
 
 	return mufs_do_lookup(fs, page, entry, depth - 1, va, new_page,
@@ -171,6 +174,11 @@ int mufs_extend_tree(struct mufs_tree *tree, uint8_t depth)
 			return -1;
 		}
 
+		if (flash_sync(dev) < 0) {
+			mufs_free_block(fs, root);
+			return -1;
+		}
+
 		tree->root = root;
 	}