diff --git a/protocol/files/chunkspec.go b/protocol/files/chunkspec.go
index 8041da2..a69be77 100644
--- a/protocol/files/chunkspec.go
+++ b/protocol/files/chunkspec.go
@@ -13,7 +13,7 @@ type ChunkSpec []uint64
 // CreateChunkSpec given a full list of chunks with their downloaded status (true for downloaded, false otherwise)
 // derives a list of identifiers of chunks that have not been downloaded yet
 func CreateChunkSpec(progress []bool) ChunkSpec {
-	chunks := []uint64{}
+	chunks := ChunkSpec{}
 	for i, p := range progress {
 		if !p {
 			chunks = append(chunks, uint64(i))