diff --git a/data.go b/data.go
index 2f3eacb..049f812 100644
--- a/data.go
+++ b/data.go
@@ -164,7 +164,7 @@ func (df *DataFragment) DataBlocks(dataType uint8, confirm bool) ([]*DataBlock,
 
 		store := int(block.Length)
 		if df.Stored-stored < store {
-			store = df.Stored - store
+			store = df.Stored - stored
 		}
 		copy(block.Data, df.Data[stored:stored+store])
 		stored += store