diff --git a/nixos/modules/testing/test-instrumentation.nix b/nixos/modules/testing/test-instrumentation.nix
index d94e21d681f..ed4cfa7805e 100644
--- a/nixos/modules/testing/test-instrumentation.nix
+++ b/nixos/modules/testing/test-instrumentation.nix
@@ -102,8 +102,12 @@ with import ../../lib/qemu-flags.nix { inherit pkgs; };
         MaxLevelConsole=debug
       '';
 
-    # Don't clobber the console with duplicate systemd messages.
-    systemd.extraConfig = "ShowStatus=no";
+    systemd.extraConfig = ''
+      # Don't clobber the console with duplicate systemd messages.
+      ShowStatus=no
+      # Allow very slow start
+      DefaultTimeoutStartSec=300
+    '';
 
     boot.consoleLogLevel = 7;