diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a1774be..9ceb0af 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,6 +15,13 @@ build:debian-testing:
     paths:
       - install/
 
+build:rt-tests:
+  stage: build
+  tags:
+    - nix
+  script:
+    - nix build -L --tarball-ttl 0 --file nix/rt.nix bsc.ovni-rt
+
 build:old-gcc:
   stage: build
   tags:
@@ -29,9 +36,9 @@ build:old-gcc-no-lto:
   script:
     - nix build -L --tarball-ttl 0 --file nix/rt.nix bsc.oldOvnisNoLTO
 
-build:rt-tests:
+build:old-gcc-release:
   stage: build
   tags:
     - nix
   script:
-    - nix build -L --tarball-ttl 0 --file nix/rt.nix bsc.ovni-rt
+    - nix build -L --tarball-ttl 0 --file nix/rt.nix bsc.oldOvnisRelease
diff --git a/nix/rt.nix b/nix/rt.nix
index 8439066..4dfff8b 100644
--- a/nix/rt.nix
+++ b/nix/rt.nix
@@ -98,7 +98,7 @@ let
     });
 
     oldCompilers = [
-      #pkgs.gcc49Stdenv
+      #pkgs.gcc49Stdenv # broken
       pkgs.gcc6Stdenv
       pkgs.gcc7Stdenv
       pkgs.gcc8Stdenv
@@ -118,6 +118,12 @@ let
 
     oldOvnisNoLTO = map last.genOldOvniNoLTO last.oldCompilers;
 
+    genOldOvniRelease = stdenv: (last.genOldOvni stdenv).overrideAttrs (old: {
+      cmakeBuildType = "Release";
+    });
+
+    oldOvnisRelease = map last.genOldOvniRelease last.oldCompilers;
+
     # Now we rebuild ovni with the Nanos6 and nOS-V versions, which were
     # linked to the previous ovni. We need to be able to exit the chroot
     # to run Nanos6 tests, as they require access to /sys for hwloc