diff --git a/bsc/nanos6/default.nix b/bsc/nanos6/default.nix
index 24fdf7d..2c06b12 100644
--- a/bsc/nanos6/default.nix
+++ b/bsc/nanos6/default.nix
@@ -11,11 +11,13 @@
 , papi
 , extrae
 , boost
-, enableJemalloc ? false
+, enableJemalloc ? true
 , jemalloc ? null
 , cachelineBytes ? 64
 }:
 
+assert enableJemalloc -> (jemalloc != null);
+
 with stdenv.lib;
 
 stdenv.mkDerivation rec {