diff --git a/apps/plugins/chessbox/chessbox_pgn.c b/apps/plugins/chessbox/chessbox_pgn.c
index f5f19e2688..4e16834f5c 100644
--- a/apps/plugins/chessbox/chessbox_pgn.c
+++ b/apps/plugins/chessbox/chessbox_pgn.c
@@ -48,7 +48,7 @@ static void *pl_malloc(size_t size)
     }
     else
     {
-        bufptr += size;
+        bufptr = (char*)(bufptr) + size;
         bufleft -= size;
         return ptr;
     }