diff --git a/lagarto-ox.nix b/lagarto-ox.nix
index bf8bca6..ae1c560 100644
--- a/lagarto-ox.nix
+++ b/lagarto-ox.nix
@@ -145,6 +145,7 @@
           TRACING y
           BOOTTIME_TRACING y
           STRICT_DEVMEM n
+          MMIOTRACE y
         ''
         # Disable SMP so we don't have IPI
         + ''