diff --git a/src/blockstore/blockstore_heap.cpp b/src/blockstore/blockstore_heap.cpp
index 28f92f69..8d4f6928 100644
--- a/src/blockstore/blockstore_heap.cpp
+++ b/src/blockstore/blockstore_heap.cpp
@@ -2364,7 +2364,7 @@ void blockstore_heap_t::get_meta_block(uint32_t block_num, uint8_t *buffer)
     }
 }
 
-void blockstore_heap_t::fill_block_empty_space(uint8_t *buffer, uint32_t pos)
+void blockstore_heap_t::fill_block_empty_space(uint8_t *buffer, uint64_t pos)
 {
     if (pos > dsk->meta_block_size)
     {
diff --git a/src/blockstore/blockstore_heap.h b/src/blockstore/blockstore_heap.h
index a05f817b..09c3bb5e 100644
--- a/src/blockstore/blockstore_heap.h
+++ b/src/blockstore/blockstore_heap.h
@@ -361,7 +361,7 @@ public:
 
     // get metadata block data buffer and used space
     void get_meta_block(uint32_t block_num, uint8_t *buffer);
-    void fill_block_empty_space(uint8_t *buffer, uint32_t pos);
+    void fill_block_empty_space(uint8_t *buffer, uint64_t pos);
     uint32_t get_meta_block_used_space(uint32_t block_num);
 
     // get space usage statistics